Southern and Middle Rocky Mountain Forests - IB
(Including Regionally Related Range Types)

Ponderosa Pine Forests and Associated Types or Subtypes

Arizona Ponderosa Pine Forest Range

In the southeastern portion of the Colorado Plateau (more specifically, the San Francisco Plateau Plateau of the Grand Canyon section within the Colorado Plateau physiographic province) and at the edge of the Mogollon Rim (Mogollon Plateau) above Verde Valley there is the largest conterminous ponderosa pine or western yellow pine (Pinus ponderosa) forest in North America. This ponderosa pine forest includes numerous range sites and habitat types as well as subtypes, variants, or forms of the generic ponderosa pine forest range type designated as forest cover type, SAF 237 (Interior Ponderosa Pine) by the society of American Foresters (Eyre, 1980).

In the area centered around the neat or "nifty" human community of Flagstaff, Arizona the author found examples of both 1) the ponderosa pine-Arizona fescue range type and 2) ponderosa pine-mountain muhly range type. Gambel's oak (Quercus gambelii), as--both or either--shrub and tree and numerous valuable browse plants were also major components or members of this assemblage of forest range vegetation.

Examples of this forested range plant community were presented in the following section.

As was the case for several other units of the ponderosa pine forest cover type treated in this chapter bearing the designations of Southern and Central Rocky Mountains, the Arizona ponderosa pine type (or subtype, variant of SAF 237) is not in the Rocky Mountain System, either Southern Rocky Mountain or Middle Rocky Mountain physiographic provinces (Fenneman, 1931, ps. 92-182; Thornbury, 1965, ps. 322-383). The floristic affinity of the Arizona ponderosa pine forest--like that of the Black Hills (Great Plains physiographic province) and those of the Basin and Range physiographic province--to ponderosa pine-dominated forests in the Rcoky Mountain system was such that it was deemed appropriate to include the "outliers" of the Rocky Mountain chain herein under the designation (for lack of a better one) of "regionally related" forest range types.

130. Ponderosa pine-Arizona fescue (Festuca arizonica) range- An example of the physiogonomy and simple structure of the Arizona form of ponderosa pine forest with consociation of Arizona fescue as understorey. This was the three-needle fascicle Rocky Mountain ponderosa pine (P. ponderosa var. scopulorum) and not the five-needle fascicle Arizona ponderosa pine (P. ponderosa var. arizonica). Vegetation was of climax composition and structure, and proved that forest and range resources can be used wisely to produce renewable crops of forage, wildlife (and wildlife habitat), wood, and water.

Coconino National Forest, Coconino County, Arizona. Vernal aspect (June), but severe to exceptional drought so that phenological development of fescue was delayed. FRES No. 21 (Ponderosa Pine Forest Ecosystem). K-18 (Arizona Pine Forest). SAF 237 (Interior Ponderosa Pine), an Arizona variant. There was no SRM rangeland cover type designation for ponderosa pine forest range in any region except Pacific Northwest. SRM 110 (Ponderosa Pine-Grassland) is as close as possible (eg. Festuca idahoensis vs. F. arizonica as understorey dominant)-- and that is not close enough. Pinus ponderosa Association in Yellow Pine Series 122.621 in Yellow Pine Series 122.62, Rocky Mountain Montane Conifer Forest 122.6 of Brown et al. (1998, p. 37).

131. Structure and species composition of Arizona form of parklike ponderosa pine-Arizona fescue forest- This photograph showed the local (= micro-) topography or landform of a ponderosa pine forest cover type in the Colorado Plateau of central Arizona. There was adequate regeneration of pine to maintain the open, woodland-like forest stand. The understorey consisted of a single herbaceous layer composed almost exclusively of Arizona fescue (a consociation). At other locations (microsites, perhaps) the exclusive herbaceous understorey was a consociation of Stipa neomexicana (see below). In these single-species herbaceous layers there were scattered plants or, less commonly, local populations of blue grama. These did not seem adequate to warrent interpretation of blue grama as an associate species. Interestingly, mountain muhly (Muhlenbergia montana), which is often an associate or even co-dominant species of this range type, was not found in this vegetation. Cheatgrass (Bromus tectorum) grew in trace amounts, but this was restricted to road berms.

Coconino National Forest, Coconino County, Arizona. Vernal aspect, June (exceptional drought conditions). FRES No. 21 (Ponderosa Pine Forest Ecosystem). K-18 (Arizona Pine Fores). SAF 237 (Interior Ponderosa Pine), an Arizona variant. No SRM designation for this cover type. Pinus ponderosa Association in Yellow Pine Series 122.621 in Yellow Pine Series 122.62, Rocky Mountain Montane Conifer Forest 122.6 of Brown et al. (1998, p. 37).

132. Two "photo-plots" of Arizona form of Rocky Mountain ponderosa pine-Arizona fescue forest range- These two slides revealed a more diverse vegetation than that shown in preceding ones. Vegetation in these "photo-plots" (slides) included a few widely scattered shrubs. In the first slide a shrub element (if it could be called that) was represented by rubber rabbitbrush (Chrysothamnus nauseosus) in the far-right foreground. Immediately in front of the rabbitbrush was a local population of Stipa neomexicana. As shown below, this grass species also formed a single-species herbaceous layer in parts of this ponderosa pine forest. The rest of the understorey was composed of cespitose individuals of Arizona fescue (both green and brown-- still dormant-- tufts).

In the second slide, shrubs (but clearly not a shrub layer) were represented by a species of gooseberry (Ribes sp.) seen at left foreground. The woody plant behind and to the right of the gooseberry was a yound ponderosa pine. Students should observe (in both "photo-plots") that ponderosa pine consisted of several age classes, including small trees, indicating regeneration of this species.

Vegetation shown in these photographs was the natural potential of climax stage. Many of the larger pines had the form of old-growth specimens, but even if a few logs had been "snaked" out and the range grazed by livestock these were benchmark examples of virgin vegetation (and this vegetation was shown after four dry years that rated designation of exceptional drought).

Coconino National Forest, Coconino County, Arizona. June, vernal aspect (severe to exceptional drought). FRES No. 21 (Ponderosa Pine Forest Ecosystem). K-18 (Arizona Pine Forest). SAF 237 (Interior Ponderosa Pine), an Arizona variant. No SRM designation. Pinus ponderosa Association in Yellow Pine Series 122.621 in Yellow Pine Series 122.62, Rocky Mountain Montane Conifer Forest 122.6 of Brown et al. (1998, p. 37).

133. Arizona form of Rocky Mountain ponderosa pine-Arizona fescue forest range vegetation- In contrast to the parklike or woodland-like physiogonomy of the ponderosa pine-dominated community shown above (and below), some areas of this forest had more of a vegetational mosaic or patchwork. In this "photo-plot" a natural opening consisted of a "pure" stand of Arizona fescue while an adjoining patch was a stand of young ponderosa pine so dense that it's shade prevented growth of any species beneath it resulting in pine straw-covered ground and no understorey.

The igneous parent material of the soil was portrayed by the conspicuous boulders in foreground.

Coconino National Forest, Coconino County, Arizona. Vernal (and drought) aspect, June. FRES No. 21 (Ponderosa Pine Forest Ecosystem). K-18 (Arizona Pine Forest). SAF 237 (Interior Ponderosa Pine), an Arizona variant. No SRM recognition for this cover type. Pinus ponderosa Association in Yellow Pine Series 122.621 in Yellow Pine Series 122.62, Rocky Mountain Montane Conifer Forest 122.6 of Brown et al. (1998, p. 37).

134. Arizona fescue understorey in ponderosa pine forest range- Population of Festuca arizonica with the tufted or "clumped" habit of this cespitose species. Coconino National Forest, Coconino County, Arizona. June, and still in exceptional drought.

135. Arizona fescue- Examples of individual plants of Arizona fescue in understorey of Arizona form of Rocky Mountain ponderosa pine forest. Many fescue plants in this population remained in dormancy induced by exceptional drought (worst in Arizona history). Some plants may have died from drought stress, but the ones shown here were flowering and setting seed. Coconino National Forest, Coconino County, Arizona. June

136. Panicle and spikelets of Arizona fescue- Even under conditions of exceptional drought this native festucoid grass was undergoing sexual reproduction. Range plants can take care of themselves if rangemen will give them the proverbial "half-a-chance". Coconino National Forest, Coconino County, Arizona. June.

Note on range vegetation classification: By the Daubenmire habitat type scheme of vegetation classification adopted by the United States Forest Service the range vegetation covered above would be some phase of the ponderosa pine/Arizona fescue (Pinus pondrosa/Festuca arizonica ) habitat type (Muldavin et al., 1996, ps. 26-27) or plant association (Stuever and Hayden, 1997, ps. 203-205).

137. Ponderosa pine-New Mexico feathergrass or needlegrass (Stipa neomexicana) range- Physiognomy of the "open, parklike" climax Rocky Mountain ponderosa pine forest in central and northern Arizona (Colorado Plateau) with an understorey consociation of New Mexico needlegrass. Trees may not have been old-growth individuals, but this was "pristine" vegetation that served as a model of the New Mexico feathergrass form of Arizona ponderosa pine forest range. Pines were the Rocky Mountain variety not the Arizona vriety of Pinus ponderosa, but the vegetation was designated by Kuchler (1964) as Arizona ponderosa pine forest. Students should not become confused over this distinction or designation based on location of climax plant community rather than on taxon of dominant species.

Arizona ponderosa pine ranges have several species of grasses and shrubs which may either form biologically diverse understories of one to several layer(s) or, alternatively, "species sparse" understories consisting of a single-species stand or, at most, a few species. The single-species understorey examples of Arizona fescue and New Mexico feathergrass presented here were forms of parklike ponderosa pine forest. Other ponderosa pine forests have more biological diversity as both species-richness and structural complexity (more layers in the vegetation).

Coconino National Forest, Coconino County, Arizona. Estival aspect (but under conditions of exceptional drought), June. FRES No. 21 (Ponderosa Pine Forest Ecosystem). K-18 (Arizona Pine Forest). SAF (Interior Ponderosa Pine), another Arizona variant. No SRM designation. Pinus ponderosa Association in Yellow Pine Series 122.621 in Yellow Pine Series 122.62, Rocky Mountain Montane Conifer Forest 122.6 of Brown et al. (1998, p. 37).

138. New Mexico feathergrass understorey of Arizona ponderosa pine forest- Detail of understorey of the Arizona form of Rocky Mountain ponderosa pine existing as a consociation of New Mexico needlegrass or feathergrass. Stipa neomexicana is another cespitose grass, a habit that resulted in the steppe-like appearance of this understorey.

Coconino National Forest, Coconino County, Arizona. Estival aspect, June

139. Specimens of New Mexico feathergrass (Stipa neomexicana) in ponderosa pine forest understorey- These robust plants were at seed-ripe or seed-shatter stage in a Rocky Mountain ponderosa pine parklike forest of the Arizona form. Exceptional drought conditions, but there had been enough soil moisture from winter precipitation for these cool-season natives to complete their annual growth cycle "with flying colors".

Coconino National Forest, Coconino County, Arizona. Beginning of dormant season for these denizens, June.

140. Spikelets of New Mexico feathergrass- Three mature florets of New Mexico needlegrass remained in an otherwise spent panicle. Yavapai County, Arizona. June.

141. Grains of New Mexico feathergrass- Four ripe caryopses (each still enclosed within a palea and lemma, the latter of which has a sharp-tipped callus at base of a characteristically twisted awn) of S. neomexicana. These grains showed the potential for mechanical injury to grazing animals.

Coconino National Forest, Coconino County, Arizona. June.

142. Blue grama (Boutelous gracilis)- Blue grama was an associate of the dominant Arizona fescue and New Mexico feathergrass in the understorey of the Arizona form of ponderosa pine forest. Blue grama is one of the most widespred and important range plants in North America. In fact, if blue grama is second to anything in total acreage and forage production it is little bluestem. Blue grama retains it's nutritive value better in the dormant stage than most other grass species. It's culms and leaves sometimes remain in semi-dormancy which allows the plant to "green-up" and begin photosynthesizing more quickly than those species that have to initiate all new growth from the rootcrown. This is also a major reason why blue grama remains more nutritious during the dormant season. Blue grama is an eragrostoid grass (Eragrostoideae subfamily) rather than festucoid (Festucoideae subfamily) like Arizona fescue and New Mexico feathergrass.

Coconino National Forest, Coconino County, Arizona. Delayed estival aspect due to exceptional drought, June.

143. Slender wheatgrass (Agropyron trachycaulum)- This species is another festucoid grass that is sometimes a local dominant but it did not assume the overall dominance of Arizona fescue or New Mexico needlegrass (= feathergrass) in the understorey of the Arizona form of ponderosa pine forest.

Actually most of the grass cover in this "photoplot" (the lower, tan-colored foliage) was cheatgrass (Bromus tectorum), a naturalized Eurasian annual

Coconino National Forest, Coconino County, Arizona. Peak standing crop; grain in soft dough stage (June).

144. Red threeawn (Aristida longiseta)- Red threeawn is generally an invader on most range types and sites except for desert ranges where it may even be interpreted as a climax grass (eg. in the Sonoran Desert). In the understorey of ponderosa pine forest ranges red threeawn is a "black sheep" of the grass family compared to climax and productive forage species like Arizona fescue, New Mexico feathergrass, mountain muhly, and blue grama. This invader species is, however, of value as an indicator plant (indicative of disturbances including overgrazing) the high population of which serves as a warning to the range manager. The attractive specimens seen here were growing on-- and doing "their part" to stabilize-- a road cut during an exceptional drought (worst since Arizona began keeping records). They were valuable as both an indicator species and soil protector plus provider of relatively unpalatable forage.

Coconino National Forest, Coconino County, Arizona. June.

Vegetation of the ponderosa pine forests of southwestern North America as well as adjoining parts of the juniper-pinon woodland and mixed prairie grasslands commonly have shrub species, some of which provide substantial amounts of palatable browse and thereby serve as indicator species for ecological status of the range and degree of use. Many range plant communities of these cover types have a very limited shrub element and, frequently, no shrub layer (as in the Arizona examples of pristine Rocky Mountain ponderosa pine). Some shrubs are usually present however even if as minor members of the range vegetation. Browse produced by these woody species (thus the species themselves) is of more importance than suggested by "minority" status.

145. Cliffrose (Cowaina mexicana var. stansburiana)- Cliffrose, Mexican cliffrose, Stansbury cliffrose, or quninie-bush is one of the most valuable browse plants in the Colorado Plateau and mountains of the Basin and Range provinces. However it is rather limited within it's distributional range and it's brittle branches are easily broken which can result in low vigor or death of plants even under conditions of otherwise proper degree of use. Cliffrose is rated as good to excellent for browsing wildlife like deer but only fair to poor for cattle. Nonetheless, cliffrose is easily "browsed out" on livestock ranges where animal distribution is improper or inadequate. It was one of the major browse species drastically reduced by overstocking of range animals-- both livestock and wildlife-- during the early part of the Twentieth Century. In fact, the classic (and still controversial) study of grazing capacity and wildlife populations was that of the Kaibab Plateau range and deer herd of northern Arizona in the general area where these photographs of cliffrose were taken. (Students were referred to the abbreviated but readily available discussion by Humphrey [1962, ps. 138-142 passim].)

For general discussion of cliffrose the following timeless standards were recommended: Dayton (1931, ps 49-50), McMinn !1939, p. 204-205), Forest Service (1940, B68), and Sampson and Jespersen (1963, ps.85-87). Good summaries can be gotten from the various editions of North American Range Plants by Stubbendieck, Hatch, and others (1881, 1986, 1992, 1997).

The individuals of cliffrose shown here were mature-- rather old, actually-- specimens in the San Francisco Mountains in the Grand Canyon section of the Colorado Plateau. They were both blooming and bearing fruit. Coconino National Forest, Coconino County, Arizona.

146. Young plant of Mexican cliffrose- This young specimen was growing beside the larger plants shown in the preceding slides. It was not too young to have sexual reproduction. Coconino National Forest, Coconino County, Arizona. June.

147. Fruit-laden leaders of Stansbury cliffrose- Even after four years of the worst drought (rating of exceptional) in history of Arizona weather records the cliffrose plants presented here were flowering while bearing their newest fruit crop. Coconino National Forest, Coconino County, Arizona. June (and into a four-year exceptional drought awaiting summer rains).

148. Inflorescences and fruits of Mexican cliffrose (Cowaina mexicana var. stansburiana)- This species is in the Rosoideae (rose subfamily) of the Rosaceae the members of which have the classic rose hypanthium.The cliffrose fruit is an achene, a dry indehiscent fruit whose pericarp and testa (seed coat) are separate. Other genera of this subfamily that are major browse plants include Fallugia (eg. Apache plume), Cercocarpus (eg. the various mountain mahoganies), Rosa (the many wild roses), Rubus (blackberry, dewberry, raspberry), Purshia (antelope bitterbrush), and Adenostoma (chamise and red shanks). These various plants were discussed variously thoroughout this publication

Coconino National Forest, Coconino County, Arizona. June (into the fourth year of a drought rated as exceptional when this photograph was taken).

Note: While some early authorities originally interpreted this species as Cowaina mexicana var. stansburiana, more recent authors regarded it as a separate species, Cowaina stansburiana. Likewise,other more recent workers placed Stansbury cliffrose in genus Purshia as either Purshia stansburiana or as Pursia mexicana var. stansburiana. Mexican cliffrose does hybridize with the bitterbrush, P. tridentata var.glandulosa (= P. glandulosa).

149. Patch of Apache plume (Fallugia pradoxa)- Even under conditions of an extended (four years), exceptional drought (the worst; highest drought ranking) the native browse plant was "setting the woods afire" with it's colorful fruit. Yes, paradoxically it is the plumose fruits not inflorescences that appear to "bloom" in this valuable (for browse, erosion control, aesthetics, ecological indicator) range plant. Apache plume is generally ranked as fair (more-or-less) in browse rating, but in contrast to restricted species like cliffrose Apache plume is widely distributed and often locally abundant making it more valuable than indicated by it's browse rating.

Standard references again include Dayton (1931, ps. 50-51), McMinn (1939, p. 204), Forest Service (1940, B77), and Stubbendieck and Hatch with others (1981, 1986, 1992, 1997).

Coconino National Forest, Coconino County, Arizona. June.

150. Leaders of Apache plume laden with fruit- Close-in shot of the browse shown in the preceding photograph. The fruit is an achene. Coconino National Forest, Coconino County, Arizona. June.

151. Inflorescences of Apache plume- Stamen and hypanthia of flowers were visible even from this distance. Lincoln County, New Mexico. June.

152. Scrub live oak (Quercus turbinella)- Leaves and fruit (acorn) of one of the dominant scrub oaks (species of shrub oak) in the Arizona (= interior) chaparral and southern ponderosa pine forests. Twigs, leaves, and mast (acorns) of this shrub are valuable for browse (and concentrates in instance of acorns) for numerous species of range animals. For example both the Rio Grande and Merriam's subspecies of wild turkey (Meleagris gallopavo intermedia and M. gallopavo merriami, respectively) are found within the range of scrub live oak. Acorn mast is readily eaten by upland game birds, deer, cattle, and species of the pig group such javelina or collarded peccary (Tayassu tajacu= Dicotyles tajacu) as well as destructive feral hogs (Sus scrofa domestica).

153. Outside, looking in- Physiononomy and structure of a ponderosa pine-Gambel's oak-bunchgrass forest range on the San Francisco Plateau within the Colorado Plateau physiographic province. This specific forest range was an example of the climax vegetation for this forest site (actually several forest sites were included) or variant of the interior ponterosa pine forest cover type (the Arizona or southwestern ponderosa pine form or variant).

Ponderosa pine was the the inland or interior variety Pinus ponderosa var. scopulorum. Gambel's oak was extremely variable as to morphology ranging in habit from huge (as in "humongous") trees down to low-growing shrubs. In fact, the same tree (same genetic individual, genotype) existed as both forms there being numerous clonal clumps arising from larger established "trees" (shoots). No other shrub species were present in this view. On upper, drier slopes there were plants of the suffrutescent species, Bigelow's sage or sagebrush (Artemisia biglovii). This was shown below. Large tree-sized Gambel's oak were visible to immediate right of the tall ponderosa pine.

The herbaceous layer consisted entirely of various species of grasses, most of them eragrostoid or festucoid (of subfamilies, Eragrostoideae and Festocoideae, respectively). There was one to a few individuals of forbs including the naturalized,Eurasian, perennial weed, yellow or common toad-flax (Linaria vulgaris), and the native, perennial composite, Arizona muleears (Wyethia arizonica). In essence: no forbs, no shrubs besides scrub forms of Gambel's oak.

In the view seen here--a lower, deeper soil, more mesic part of the range--the dominant grass was blue wildrye (Elymus glaucus) while slender wheatgrass (Agropyron trachycaulum= A. subsecundum) was the associate grass species. Other major grasses included wolftail (Lycurus phleoides), mountain muhly (Muhlenbergia montana), blue grama (Bouteloua gracilis), and, locally, the introduced (Eurasian) species known as intermediate wheatgrass (Agropyron intermedium).

Coconino National Forest, Coconino County, Arizona. Late July. FRES No. 21 (Ponderosa Pine Forest Ecosystem). K-18 (Arizona Pine Forest). SAF 237 (Interior Ponderosa Pine), an Arizona variant. There was no SRM rangeland cover type designation for ponderosa pine forest range in any region except Pacific Northwest. SRM 110 (Ponderosa Pine-Grassland) is as close as possible (eg. Festuca idahoensis vs. F. arizonica as understorey dominant)-- and that is not close enough. Pinus ponderosa Association in Yellow Pine Series 122.621 in Yellow Pine Series 122.62, Rocky Mountain Montane Conifer Forest 122.6 of Brown et al. (1998, p. 37).

154. Moving inside- Structure and composition of a ponderosa pine-Gambel's oak-bunchgrass forest range at climax state on the San Francisco Plateau. The first slide presented a large ponderosa pine in foreground with (in the background) a large tree of Gambel's oak having a three-pronged (three big vertical limbs) pitchfork-shaped crown with offshoots (clonal shoots) arising from near base of the massive trunk.

The second slide presented a different view with the large ponderoda pine in the first phtograph now in left midground and the large pitchfork-crowned gambel's oak with clonal offshoots in right midground. Other such oak offshoots were at left margin in the second slide. Rather thickly spaced (dense) stands of younger ponderosa pines were in the background of both slides. The same split, fallen log was in both of these photographs.

The dominant herbaceous species was blue wildrye while the associate herb was slender wheatgrass. There were some plants of the introduced intermediate wheatgrass as well as wolftail, mountain muhly, blue grama, and Arizona threeawn. Arizona threeawn was uncommon on this lower, less rocky, and less sloping part of the range than on steeper, rockier, and shallower habitats (see below).

155. View from inside- Interior of a climax ponderosa pine-Gambel's oak-bunchgrass forest range in the San Ferancisco Plateau. The forest community shown in these two rather restricted views had very few young pines (though there was probably enough regeneration to maintain current tree density) or Gambel's oak such that this was primarily a two-layered forest. Stands of smaller, younger and more densely populated ponderosa pines were visible in the distant background of these two visual perspectives.

The large, adult pines had reached their peak growth and were just entering the senescent stage of their life cycles. Logs littering the ground included both 1) fallen limbs from crowns of these adult ponderosa pines and 2) trunks of smaller pines that had died for reasons unknown to the author. A fire in the distant past of recent history had burnt over portions of this forest range (shown below), but there were no burn marks on the trunks of any of the beautiful trunks presented in these two "photoplots".

Within the area of these two photographs the dominant herbaceous species was slender wheatgrass while the associate species was blue wildrye. Mountain muhly, wolftail, blue grama, Arizona threeawn, and the agronomic species, intrmediate wheatgrass were present with smaller cover and lower density. There were no forbs except the Eurasian weed, yellow or common toad-flax and the native composite, Arizona muleears.

156. Co-dominants at different stages- Young adult ponderosa pine and a clonal clump of Gambel's oak in a ponderosa pine-Gambel's oak-bunchgrass forest range in the San Ferancisco Plateau. The shoots of Gambel's oak appeared to be too immature to bear acorns (still at pre-sexual maturity stage of their life cycle).

157. Pals, woody and herbaceous- "Nested photoplots" of slender wheatgrass to the fore of a shoot of Gambel's oak in the shrub and herbaceous layers of a ponderosa pine-Gambel's oak-bunchgrass range in the San Francisco Plateau. It was not determined if this shoot of Gambel's oak was a clonal offshoot (ramet) or a large seedling (a genet or unique genotype).

Coconino National Forest, Coconino County, Arizona. Late July.

158. It can do it either way- A lone seedling of Gambel's oak (and a seedling at considerable distance from the nearest clone of this species) provided an example that Gambel's oak reproduces both sexually (as here) and asexually (as shown immediately above and throughout this section).

This baby plant was on the floor of the ponderosa pine-Gambel's oak-bunchgrass forest range featured here. "Pine straw" (accumulated needles of ponderosa pine) and a small plant of some lupine (Lupinus sp.) along with an unidentified grass completed this snapshot of life on this forest range.

Coconino National Forest, Coconino County, Arizona. Late July.

159. Some of the critical characters- Series of three "nested" (or "telescoped") "photoplots" of the plant community of a ponderosa pine-Gambel's oak-bunchgrass forest range in the San Ferancisco Plateau. This local area of the range that was covered in this section had burned sometime in the distant past. The flame-burnished basal trunk of the large pine attested to that fact as did charred remains of limbs and logs that had been on the ground at time of fire.

Gambel's oak was represented by three shoots in right foreground of the first slide. The brown (dead) leafes in upper crowns of these three shoots was stress from prolonged drought that was at Palmer Index category of Extreme to Extraordinary Drought at time of photographs. There were also Gambel's oak shoots (shorter than the three just mentioned) in the left distant background of all three photographs. The two conifer saplings (foremost one blocked view of the second in the second and third of these "photoplots") to immediate left of large ponderosa pine were alligator juniper (Juniperus deppeana). Alligator juniper is one of the few Juniperus species that resprouts following fire or wood cutting. It was not known if these two alligtor juniper had been present at time of the most recent fire, but such did not appear to be the case, there being no charred juniper trunks.

The dominant herbaceous species in the forest community presented in these three slides was slender wheatgrass. Associate herbaceous species (second most abundant grass) was mountain muhly. Other important (common in this range plant community) grasses included wolftail, sideoats grama, blue grama, and Arizona threeawn. There were no plants of blue wildrye or intermediate wheatgrass on this upper slope. The only forb "to amount to anything" was the the naturalized, Eurasian, perennial weed known as yellow or common toad-flax (Linaria vulgaris), an aggressive, hard-to-control invader (Whitson et al., 1992, ps. 548-549).

160. Major herbaceous characters- Herbaceous layer, a sward of cespitose native grasses, of a ponderosa pine-Gambel's oak-bunchgrass forest range in the San Ferancisco Plateau. These two slides were "nested photoplots" of the herbaceous layer shown in the immediately three slides (flame-burnished basal trunk of the big ponderosa pine and lower shoot of the foremost alligator juniper in the first of these two slides served as '"plant landmark").

The herbaceous assemblage in the first slide was a consociation of mountain muhly, overall associate herbaceous (grass) species. The second slide (the "nested plot") featured a large plant of mountain muhly (right) and several plants of wolftail (left).

161.Another part of the forest community- A local, rocky, south-facing low slope within a ponderosa pine-Gambel's oak-bunchgrass forest range in the San Ferancisco Plateau. This xeric microhabitat supported a consociation or local population of sideoats grama with a few scrubby, shrub-scale plants of Gambel's oak. This was another part of the same forest range that was featured in this section. This mini-sized south-slope habitat with its sideoats grama-Gambel's oak assembly joined (was immediately adjacent to) the portion of this forest range community featured in the two immediately preceding slide-caption sets.

An even rockier, more xeric microenvironment in this ponderosa pine-dominated forest was presented in the next slide …

162. Where its even rockier- A rocky, shallow, steep, southwestern slope was a harsh local evnironment (microsite or microhabitat) within the same forest range that has been being described. This native vegetation was a ponderosa pine-Gambel's oak-bunchgrass forest range in the San Ferancisco Plateau.

The understorey presented in this "photographic dendrogram" consisted of two local grass-dominated communities: 1) sideoats grama (similar to the one featured immediately above which, incidentally, abutted this "photosample" of range vegetation) and 2) Arizona threeawn (Aristida arizonica). The Arizona threeawn-dominated herbaceous community was the subject of the next slide …

163. Grass on the rocks- Two" photoplots" at two locations on a steep, rocky, shallow-soil microhabitat on which local range plant communities were: 1) in first slide, a mixture of Arizona threeawn (Aristida arizonica) and slender wheatgrass and 2) in second slide, an herbaceous assembly of slender wheatgrass, wolftail (with conspicuous contracted panicles), Bigelow's sgebrush (Artemisia bigelovii), Missouri goldernrod (Solidago missouriensis), and the naturalized Eurasian weed, yellow or common toad-flax.

These two local range communities were on a ponderosa pine-Gambel's oak-bunchgrass forest range in the San Ferancisco Plateau. This is the same forest range that has been the subject--the example--of this part of the section devoted to Arizona ponderosa pine forest range.

Coconino National Forest, Coconino County, Arizona. Late July.

164. Parting interior view- Two views deep inside a ponderosa pine-Gambel's oak-bunchgrass forest range in the San Ferancisco Plateau presenting the composition and internal structure of a climax stage of the Arizona variant of this forest range type (SAF 237, Interior Ponderosa Pine). Small plants of Gambel's oak were present as, for example, in left-central midground of the second of these two slides. Dominant grass species was slender wheatgrass. Major grass species included Arizona threeawn, mountain muhly, wolftail, blue grama, sideoats grama, and blue wildrye. There were no forb species in view of these two "photoplots".

Note on range vegetation classification: By the Daubenmire habitat type scheme of vegetation classification adopted by the United States Forest Service the range vegetation covered above would be some phase of the ponderosa pine/Gambel oak (Pinus pondrosa/Quercus gambelii) habitat type (Muldavin et al., 1996, ps. 28-30) or plant association (Stuever and Hayden, 1997, ps. 227-229).

Gambel or Gambel's oak (Quercus gambelii) is a widely distributed species of the white oak group (Leucobalanus subgenus) with a species (biological) range extending from the Chihuhuan Desert of Chihuhua north- and eastward to the plains of South Dakota and west to southern Nevada (Elias, 1980 ps. 329-330). Throughout this species range Gambel oak grows primarily in the range communities of the foothills up through various range types of montane forest vegetation. Gambel's oak is a white oak (subgenus, Leucobalanus).

Gambel's oak more commonly occurs as a shrub. In fact, its occurrence in tree form is apparently so uncommon that neither the standard Dendrology text for North American tree species (Harlow et al., 1979) nor the current "bible" of North American silva (Burns and Honkala, 1990) included Gambel oak. As viewers can see below Gambel's oak does grow to tree shape and size; in point of fact, to immense "oak tree size". It is amazing how the leading authorities sometimes "totally miss it".

In the classic manual of trees in North America, Sargent (1933, p.297) described Gambel's oak, which he labeled Quercus utahensis, as "[a] tree, occasionally 30 feet high, with a trunk 4 inches-8 inches in diameter". Kearney and Peeblies (1960, p. 219) and Vines (1960, ps. 161-162) explained that Gambel's oak ranges in size and shape from thicket-forming shrubs as tall as six and a half feet to trees growing fifty feet in height. Kearney and Peeblies (1960, p. 219) listed Q. submollis as a synonym for Q. gambelii. In the classic Flora of New Mexico Wooton and Stanley (1915, ps. 172-174) described Q. utahensis varying from clump-like shrubs to solitary trees, Q. novomexicana ranging from "a shrub" to "a good-sized tree", and Q. submollis ("a low tree or shrub"); but they explained that Q. gambelii would be the single species of white oak in New Mexico if the "…numerous easily recognizble variants of that type…" were ignored.The most descriptive scientific name of this woody species that varies from a sprawling shrub with colony growth form to masive hardwood tree (the plant now called Gambel's oak) was Quercus confusa as used by soem of the early taxonomists.

There has been but limited study into biology and ecology of Gambel's oak (eg. this species was not included in Silva of North America [Burns and Honkala, 1990]). Ryniker et al. (2006) described what they called "structure of Quercus gambelii communities" which included such features as density and basal area of "trees" and age/size classes, but they examined stands of trees (not communities per se; in fact, these were more like populations of Gambel's oak within woody plant communities). Nor did Ryniker et al. (2006) distinguish between genetic individuals or even note the clonal structure/morphology and colony forming characteristic of Gambel's oak

Most of the research involving Gambel's oak involved control of this species in situations where it has become a noxious (ie. brush) species. A study of this aspect, and one that included a thorough reveiw of the Gambel's oak literature up to that point in time, was that of Engle et al. (1983). Muller (1951) seemed to be the best work regarding the clonal or modular nature of Gambel's oak.

General sources for Gambel's oak included Range Plant Handbook (Forest Service, 1940, p. 12) which was best overall from a range plant/range vegetation perspective. Best coverage from a botanical and general view was, in this author's experience, that of (Elias, 1980, ps. 329-330) with the timeless Vines (1960, ps. 161-162) also giving good summary treatment. Lamb (1989, p. 14) briefly mentioned Gambel's oak, but showed distribution by counties in southwesterrn North America. The author of the current publication found it inexplicable tha Q. gambelii was omitted from both the Forest Service's encyclopedia of United States shrub species (Francis, 2004) and that of U.S tree species (Burns and Honkala, 1990). As shown immediately below the silva of the Coconino National Forest (among numerous othernational forests) felt rebuffed and completely rejected.

165. Its a shrub species; its a tree species- A local group of Gambel's oak ranging from large trees (see immediately below) to clumps of multi-stemmed shrubs. It is commonly accepted that Gambel's oak is a highly clonal woody species that primarily reproduces asexually from a system of lignotubers, vast network of woody rootstocks or rhizomes, thereby being capable of covering extensive areas (eg. an entire hillside). Gambel's oak is much like the associated quaking aspen (Populus tremuloides) is this regard. Apparently, this is surprisinglhy little in the scientific literature regarding this feature of Gambel's oak.

It was highly likely that all shoots (from massive oak "trees" to "scrub shoots") were all offshoots or trunks from subterranean lignotubers and/or woody rhizomes so that they were in effect branches off of underground trunks or limbs of the same genetic Gambel's oak (ie. one genotype). This logical conclusion was an "educated hunch" not a genetically determined fact. There were three "damn big" tree-size trunks and over twenty shrub-size trunks (shoots) in this local group of Gambel's oak. Details of two of the tree-size trunks were presented in the immediately succeeding two slides.

This local grove or colony of Gambel's oak was growing in a general, open understorey ponderosa pine forest community; more precisely, a ponderosa pine-Gambel's oak habitat type with an herbaceouslayer of mixed grass species. Several large ponderosa pines were visible in right background of this photograph.

Coconino National Forest, Coconino County, Arizona. Mid-July.

166. One tree or several? Two big trunks of Gambel's oak in a local group or grove introduced in the preceding slide-caption set. Both of these tree trunks or boles were approximately one and a half feet in diameter (DBH). Bark on them was characteristic of mature bark of Gambel's oak.

A thought-provoking exercise is to ask whether these two trunks were two separate (individual) trees (two genetotypes or genetically distinct genetic individuals from two separate acorns) or if there were two mature shoots of the same tree (the same genotype). The latter was the most probable answer (explanation). Also, the shrub-size trunks (of which there were over twenty in this local group) were most likely other offshoots of the same trtee (same genotically unique plant) that had not reached mature of adult size. Probably all of these clonal units were merely limbs or large distinct branches off of the same lignotuber or subterranean network of rootstocks (= woody rhizomes).

Coconino National Forest, Coconino County, Arizona. Mid-July.

167. Shrubs or baby trees? A clump of numerous shoots (first slide) and a single shoot (second slide) of Gmbel's oak in a lower woody layer of a ponderosa pine-Gambel's oak-mixed grass montane forest. Both the clump and the single shoot were growing about fifteen feet of each other. Was the clump and the individual shoot parts of the same plant (same genetic individual) or where these two separate plants (two genotypes)? Clearly the clump of shoots was the same plant with individual shoots being clones or offshoots from the same lignotuber, but was the individual shoot another clonal unit or was it a small sapling of a genetically distinct (separate or second) genotype (genetically unique tree)?

Without genetic analysis, such as DNA testing ("DNA fingerprinting"), there is no way to know. Gambel's oak has both asexual (an example of a Gambel oak seedling was presented below) and sexual reproducution, but asexual or vegetative reproduction predominates.

Coconino National Forest, Coconino County, Arizona. Mid-July.

168. Studies in trunks and leaves- Bark and leaves on a large (foot and a half DBH) Gambel's oak (first photograph) and on a sapling-size shoot (second photograph) of Gambel's oak in a ponederosa pine-Gambel's oak-mixed grass montane forest. The large trunk with basal leaves was on one of the large "trees" (offshoots) shown in the second slide immediately above; specifically, the trunk on the right of the horizontal phyotograph. The smaller shoot or bole with cluster of leaves shown at closer distance (second photograph) was probably another offshoot of the same tree, the same genetypic individual.

Viewers can readily see from leaves shown in these photographs that Gambel's oak is in the white oak group (subgenus, Leucobalanus).

Coconino National Forest, Coconino County, Arizona. Mid-July.

169. Young juniper amid pines, oaks, and grass- Three-trunk sapling of alligator juniper (Juniperus dippeana) in understorey of ponderosa pine-gambel's oak-mixed grass montane forest (Pinus ponderosa-Quercus gambelii habitat type).

This open, parklike ponderosa pine forest range joined natural range communities of pinyon pine (P. edulis)-juniper woodland and savanna. In addition to alligator juniper (the least common Juniperus speceis) the other junipers were Utah juniper (J. osteosperma), Rocky Mountain juniper (J. scopulorum) , and oneseed juniper (J. monosperma). Examples of these other three Juniperus species on juniper-pinyon pine woodland range that adjoined this forest were shown in the chapter, Juniper-Pinyon Woodland.

Coconino National Forest, Coconino County, Arizona. Mid-July.

170. Slender shoots under sparse pines- Slender wheatgrass (Agropyron trachycalulum= A. subsecundum= A caninum, at least in part) in herbaceous understorey of a ponderosa pine-Gambel's oak-grass montane forest range in the Colorado Plateau of northcentral Arizona. Slender wheatgrass was the overall dominant grass--dominant herbaceous species, for that matter--especially on shallow upslopes. It was a local associate herbaceous species on lower more mesic habitats where blue wildrye (Elymus glaucus) was the dominant herb. As readily ascertained from these photographs (and the first one in the next set) slender wheatgrass is strictly a cespitose (bunchgrass) species.

The two closely resembling species of bearded wheatgrass (A. subsecundum) and slender wheatgrass (A. trachycaulum) were recognized in traditional treatments such as those by Hitchcock and Chase (1950, ps. 231, 238-239) and Kearney and Peebles (1960, ps. 92-94). A widespread older binomial was A. pauciflorum (Forest Service, 1940, p. G5). Gould (1951, ps. 111-112, 120-121) kept these two taxa distinct but as subspecies of Elymus pauciflorus! In Arizona Range Grasses Humphrey (1960, ps6-7), designated slender wheatgrass as Agropyron trachycalulum but in the next edition Ruyle and Young (2003, p. 60-61) changed slender wheatgrass back to Elymus, but as E. trachycaulus! Welsh et al. (1993, p. 820) also used E. trachycaulus. In the latest definitive--definitive based on cladistic criteria--encyclopedia of North American grasses Barkworth et al. (2007, ps. 321-323) interpreted slender wheatgrass as Elymus trachycaulus subsp. trachycaulus (in contrast to E. trachycaulus subsp. subsecundus to which they applied the common name, one-sided wheatgrass). Did you follow all that?

Through all this FUBAR name change--"musical names"--the common name of slender wheatgrass remained. Of course we "lesser lights" are told how superior scientific names are compared to common names. We can all agree that scientific names are superior for the purpose of getting new publications in the taxonomic literature (and resultant academic promotions).

The pertinent point is that slender wheatgrass is a dominant climax grass of montane forest ranges that furnishes feed rated as Good to Excellent in forage value. It provides outstanding soil cover on important forest watersheds. In ponderosa pine forest ranges slender wheatgrass is one of the major forage-producing range plants for early spring green-up. The species (biological) range of slender wheatgrass (in the strict sense not the entire E. trachycaulus complex described above) extends from deep south Mexico to southern portions of the Prairie Provinces eastward to Newfoundland, north to Alaska and west to the Pacific Ocean. The importance of slender wheatgrass is attested to by its being on the Society for Range Manageament Master Plant list of 200 species for the International Range Plant Identification Contest--and under whatever binomial was fashionable at time of that edition, as for example Agropyron trachycaulum in Stubbendieck et al. (1992, ps. 204-205).

Description and discussion in the Range Plant Handbook (Forest Serviece, ps. G5), again as Agroypron pauciflorum (and still the common name of slender wheatgrass), remained one of the best treatments of this species. A fine summary of slender wheatgrass that was much more current (and a favorite of the current author) was Tilley et al. (2011).

On the pine-oak grass montane forest range treated here, slender wheatgrass had already flowered, set and, then, shed grain. Blue wildrye on this same range was in peak to late anthesis by time slender wheatgrass had passed the grain-shatter stage and was entering senescence. The Extrene Drought (Palmer Scale) in which these plants were growing might well have hastened plant maturity of slender wheatgrass.

Coconino National Forest, Coconino County, Arizona. Mid-July; post grain-shatter stage, perhaps entering drought-induced dormancy.

171. Slender bottoms and tops- Specimens of slender wheatgrass on a ponderosa pine-Gambel's oak-grass mountain forest range showing basal shoots, especially leaves (first photograph) and upper sexual shoots with spikes from which grain had already shed (second photograph). The inflorescence of slender wheatgrass is a spike-like or a very open spike (if there is such a thing) that has more recently been described as a spicate raceme (Tilley et al., 2011). It has traditionally been regarded as a spike (Hitchcock and Chase, 1950, p. 238; Jepson, 1953, p. 101; Welsh et al., 1993, p. 820; Skinner, 2010, p. 422). Skinner (2010, p. 422) specified that the rachis is continuous and thus not breaking like the rachis of the traditional Elymus species. That feature was evident in the second of these photographs.

Although cespitose, slender wheatgrass does, sometimes, have short rhizomes (Jepson, 1953, p. 101; Welsh et al., 1993, p. 820). Most leaves of slender wheatgrass plants are at bases of plants (first slide) Slender wheatgrass is best described as a short-lived perennial (Tilley et al., 2011).

Coconino National Forest, Coconino County, Arizona. Mid-July; post grain-shatter stage, perhaps entering drought-induced dormancy.

172. Blue on the forest floor- Two plants of blue wildrye (Elymus glaucus) growing on the forest floor of a ponderosa pine-Gambel's oak-grass range community in the Colorado Plateau of northcentral Arizona. These two plants were growing on shallow, stoney soil at base of a slope in a forest range on which slender wheatgrass was the overall dominant herbaceous species of the understorey. Wolftail, sideoats grama, and Arizona threeawn were other local associates on this upland forest range.

These two specimens were small plants compared to individuals of blue wildrye found on bottomland range sites in the Arizona Transition Zone.

Blue wildrye is a widespread and valuable forage species across the Western Range Region (and, as far as that goes, across much of North America). For all of its importance as a range plant, however, blue wildrye has received relatively little attention. For example, blue wildrye was not included in the University of Arizona publication, Arizona Range Grasses (Humphrey, 1960; Ruyle and and Young, 2003). Gould (1951, ps. 118-119) did provide taxonomic coverage of blue wildrye. Good general references for blue widlrye as a range plant and forage species included the old standby, Range Plant Handbook (Forest Service, 1940, G53), and Dyer et al. (2005).

Coconino National Forest, Coconino County, Arizona. Mid-July; peak to late anthesis.

173. Blue spikes- Examples of spikes (spike type inflorescence) of blue wildrye growing in the herbaceous understorey of a ponderosa pine-Gambel oak-grass montane forest range in the Colorado Plateau of northcentral Arizona. Gould (1951, ps. 118-119) noted that there is usually only one spikelet per node of the rachis in blue wildrye.

Coconino National Forest, Coconino County, Arizona. Mid-July; peak anthesis.phenological stage.

Location Note: other examples of blue wildrye in Range Types of North America were included in chapters, Miscellaneous Forest Types- II (Riparian Zone Forests- Arizona Uplands [Transition Zone}) and Pacific Northwest Forests (Pacific Douglas-fir Forest Range).

174. Another member of the understorey- Three cespitose plants of mountain muhly (Muhlenbergia montana) in the herbaceous layer of the ponderosa pine-Gambel's oak-grass montane, forest range being treated in this section. Details of mountain muhly were covered earlier (above) in this chapter so such details were not re-presented in this or the following caption.

Plants seen here had been in Extraordinary Drought until a few days prior to these photographs after which water-starved shoots had made considerable growth. Although mountain muhly is typically a climax dominant grass in open ponderosa pine forest ranges (see again above), on this particular range mountain muhly was dominant only in a few isolated microlocations like the one seen here.

Coconino National Forest, Coconino County, Arizona. Mid-July; early stages of shoot growth and development..

175. More muhly- Two "really big" plants with smaller neighboring plants (first slide) and particulars of a third plant (second slide) of mountain muhly in the understorey of a ponderosa pine-Gambel's oak-mixed grass montane forest range in the Colorado Plateau of northern Arizona.

It was remarked in the preceding caption that this growth had been made in an Extraordinary Drought that had broken with light rains only a few days prior to time of these photographs. The dead tissue still on these plants (eg. straw-colored shoots bearing panicles) was last year's growth.

Mountain muhly has a species range extending from deep into Mexico north to British Columbia but mostly limited to the Rocky Mountain Range. The species has been included on the Master Plant List of 200 species for the International Range Plant Identification Contest held by the Society for Range Management (Stubbendieck et al., 1992, ps. 124-125). "Tried and true" treatment of mountain muhly was presented in the Range Plant Handbook (Forest SErvice, 1940, p. G81).

Coconino National Forest, Coconino County, Arizona. Mid-July; early stages of shoot growth and development..

176. Wolfing in the woods- Several cespitose plants of wolftail (Lycurus phleoides) in the herbaceous understorey of a ponderosa pine-Gambel's oak-mixed grass forest range (a Ponderosa Pine-Gambel Oak habitat type). Wolftail was an associate grass species in this range type in which the local dominant herbaceous species was slender wheatgrass (Agropyron subsecundum= A. trachycaulum).

Coconino National Forest, Coconino County, Arizona. Mid-July; shoot maturity, grain-shatter stage.

177. Arizona on the rocks- Four cespitose plants (three in the first of these two slides) provided examples of Arizona threeawn (Aristida arizonica) that was locally abundant on the ponderosa pine-Gambel oak-grass range being described in this section. On this forest range Arizona threeawn grew on and dominated the shallowest, steepest, tmost rock-strewn microsites. Specimens in these photographs were growing under conditions of Extraordinary Drought and still had last year's inflorescences remarkably intact with almost all spikelets completely unshed along with this year's early season shoot growth (from recent rains). Made for neat examples of this species.

Many of the Aristida species are very similar in morphology and taxonomic interpretations of species vary among various "lumpers" and "splitters". A. arizonica is so morphologically unique that agrostologists from Hitchcock and Chase (1950, p. 477-478) to Barkworth et al. (2003, p. 335) have consistently recognized this species. Aristida more than almost any Gramineae genus (with possible exception of the rosettte Panicum species) are subject to interpretation--usually rather arbitrary at that--and have been rearranged about as much as any North American grass species. A. arizonica is very distinctive with its comparatively small size and compact clumped habit growing on its favored habitat of xeric, shallow, rocky slopes (Gould, 1951, ps. 242-243).

None of the Aristida species are preferred by grazing animals, but the threeawns or wiregrasses are utilized as forage, though more on harsh environments such as desert ranges than on favorable range habitats where more palatable plant species are abundant.

Coconino National Forest, Coconino County, Arizona. Mid-July; early shoot growth stage along with last year's unweathered sexual shoots.

178. Ears among the rocks- A plant of Arizona muleears (Wyethia arizonica) in the understorey of a ponderosa pine-Gambel's oak open upland forest. This specimen was growing in the shallow bed of an ephemeral stream (more like a drainage) in this open, parklike forest range.

In Notes on Western Range Forbs Hermann (1966, p. 347) remarked that palatability of this species was "very low". The specimen presented here had no visible evidence of any defoliation.

Coconino National Forest, Coconino County, Arizona. Late July; fruit-ripe stage..

179. Heads above the ears- Two heads or capitula with ripe achenes (first slide) and topdown details of achenes in a head (second slide) of Arizona muleears. These units or organs were on the same plant that was shown in the immediatlely preceding two slides.

Coconino National Forest, Coconino County, Arizona. Late July; fruit-ripe stage..

Location Note: a riparian or gallery forest of hardwood species in the physiographic province known as the Transition Zone (Central Highlands) was included in Range Types of North America chapter, Miscellaneout Forests- II.

180. Lightening-struck ponderosa pine- The ponderosa pine cover type is definitely a fire type. Volumes have been written about the role of fire-- both natural and anthropogenic-- in maintenance of these forest and range ecosystems. The historic fire regime was one on high frequency-low intensity such that commonly there was not a build-up of fuel and development of a fire staircase that allowed surface fires to develop into crown fires.

Lightening strikes are the main ignition source for natural forest fires. This mature ponderosa pine standing sentry atop the local high point bore the obvious mark of a direct hit by lightening that could have lead to a forest fire. Whatever fire conditions existed, whether any fire started by such ignition is a low-intensity surface fire or a holocaustic crown fire would depend on fuel. Even if the forest is as dry as the proverbial tenderbox climax ponderosa pine forests with grassy understories like those dominated by Arizona fescue and New Mexico feathergrass are much less likely to become "hell on earth" than those with numerous layers of vegetation leading staircase-like to the forest canopy.

This is the lesson of prescribed burning and proper grazing management on ponderosa pine ranges. Some grazing by livestock and/or big game species reduces buildup of vegetative material that can serve as fuel. Undergrazing of the forest understorey can contribute to destructive crown fires, but so can overgrazing. Prologued overuse that leads to range deterioration leaves the land with less cover as protection against soil erosion. Perhaps even more important in immediate outcome is weakening of the climax grasses which leaves them at a competitive disadvantage against woody plants. This results in increases in shrubs and trees which permits development of the fire staircase as well as leaving the soil surface with less herbaceous growth to break the impact of rain drops or hold back melt water. Understorey management is a key component in proper management-- including wise use-- of fire as a component of ponderosa pine ranges.

Looked at in this perspective, the more-dead-than-alive pine with the "blowed off" crown and the lightening blaze is "a thing of beauty".

Coconino National Forest, Coconino County, Arizona. June.

181. Another form or subtype of the ponderosa pine forest range type is this one in the inland Pacific Northwest where the herbaceous understory layer is dominated by bluebunch wheatgrass and the shrub understory dominants are snowberry and antelope bitterbrush. This is a transition vegetation type or broad ecotone in the Columbia Basin between Palouse Prairie and the ponderosa pine zone of the Blue Mountains and Okanogan Highlands. In the classic Natural Vegetation of Oregon and Washington Franklin and Dryness (1973, p. 172-180) identified both ponderosa pine/ bluebunch wheatgrass and ponderosa pine/ bitterbrush/ bluebunch wheatgrass associations as transitions "between steppe or shrub-steppe and forest". Interior ponderosa pine type. Spokane County, Washington. FRES No. 21 (Ponderosa Pine Ecosystem). K-10 (Western Ponderosa Pine Forest).SAF 237 (Interior Ponderosa Pine). Yellow Pine Series of Brown et al. (1998).

Technical explanation: this example from the Northern Rocky Mountains was inserted here to show 1) the floristic affinity of vegetation of the Northern Rocky Mountains with those of the Central and Southern Rocky Mountains and 2) the continuity and variation within the general ponderosa pine type.

182. Douglas fir montane forest type-- interior Douglas fir type-- in Southern Rocky Mountain- This dense stand of Rocky Mountain Douglas fir is a north slope community along the Frasher River at an elevation of 8,000 to 9,000 feet. Canadian life zone of C. Hart Merriam. Arapaho National Forest, Gilpin County, Colorado. FRES No. 20 (Douglas Fir Ecosystem). K-11 (Douglas-fir Forest). SAF 210 (Interior Douglas-fir). Pseudotsuga menziesii Association in Douglas Fir-White Fir (Mixed Conifer) Series of Brown et al. (1998).Southern Rockies-Crystalline Mid-Elevation Forests Ecoregion, 21c (Chapman et al., 2006).

183. Interior Douglas fir forest range type growing on a bottomland or alluvial site along the Snake River— Ponderosa and limber pine (Pinus flexilis) are associated upperstory species. The herb layer is dominated by Poa, Festuca, andStipa species. Transition life zone of C. Hart Merriam. Targhee National Forest, Lincoln County, Wyoming.

FRES No. 21 (Douglas Fir Ecosystem).K-11 (Douglas-fir Forest). SAF 210 (Interior Douglas-fir). Pseudotsuga menziesii-mixed conifer Association in Douglas Fir-White Fir (Mixed Conifer) Series Series 122.61 of Rocky Mountain Montane Conifer Forest biotic community 122.6 of Brown et al. (1998). Middle Rockies- Mid-Elevation Sedimentary Mountains Ecoregion, 17g (Chapman et al., 2003).

184. Mesic form of Rocky Mountain mixed conifer type- In the moist valley of Middle Saint Vrain Creek a mixed conifer forest developed in which Douglas-fir and Colorado blue spruce (Picea pungens) were co-dominant and white fir (Abies concolor) was the overall associate. Lodgepole pine was abundant and a local associate species though more commonly a distant fourth-place conifer to the other coniferous trees. The most common angiosperm tree species were Rocky Mountain willow (Salix monticola) closest to the stream and quaking aspen and Rocky Mountain maple (Acer glabrum) on higher ground farther from the actual riparian zone. Tthinleaf alder (Alnus incana subsp. tenuifolia) and water birch (Betula occidentalis= B. fontinalis) were associate species to Rocky Mountain willow in the range plant community of the riparian zone.

Herbaceous species were mostly limited to the riparian zone and a less shaded margin between riparian and the fully formed mixed conifer forest with nearly complete closed canopy. Herbaceous species included wooly or hairy arnica (Arnica mollis) and common blankeflower (Gaillardia aristata).

Roosevelt National Forest, Boulder County, Colorado. Early July (estival aspect). Elevation: about 8000 to 8500 feet. FRES No. 21 (Douglas Fir Ecosystem).K-11 (Douglas-fir Forest). SAF 210 (Interior Douglas-fir). Pseudotsuga menziesii-Mixed Conifer Association 122.613, Douglas-fir-White Fir (Mixed Conifer) Series 122.61 of Rocky Mountain Montane Conifer Forest biotic community 122.6 (Brown et al., 1998, p. 37). Southern Rockies- Crystalline Mid-Elevation Forests Ecoregion, 21c (Chapman et al., 2006).

185. Conifer mix along a mountain stream - Rocky Mountain mixed conifer community that developed in the floodplain of Middle Saint Verain Creeek. Douglas-fir and blue spruce were co-dominant while white fir was the asociate in most locations with lodgepole pine the associate species at fewer and smaller local environments. Along the streamside margin (riparian zone) of this conifer-dominated forest Rocky Mountain willow was dominant with thinleaf alder and water birch lesser species.Within this Douglas-fir-mixed conifer forest quaking aspen and Rocky Mountain maple were the most important deciduous tree species.

Blue spruce were readily distinguished by their light, bluish or silverish needles. Although blue spruce usually tend to be smaller trees the tall and rather immense conifers in the first photograph were Colorado blue spruce. These remarkable trees were of recordbreaking-like dimensions. Douglas-fir are generally the largest conifers in bottomland habitats in this region, but in this creek bottom forest blue spruce held that distinction. An example of a typical large Dopuglas-fir was shown in the next slide-caption set.

There was almost no understorey in this shade-dense, closed canopy, mesic bottomland forest. There were several herbaceous species in a transition zone between the riparian willow-alder-birch scrub and outer margin of the mixed conifer forest. Most abundant of these herbs were the forbs wooly or hairy arnica and common blankeflower.

186. Moist and mixed- Species composition of a mesic, montane mixed conifer forest that developed in the valley of Middle Saint Vrain Creek in the Suthern Rocky Mountains.Douglas-fir are typically the largest individual trees (height, DBH, crown size) in bottomland coniferous forest in this region, but, as shown immediately above, blue spruce held that distinction in this particular forest. The more typical case of Douglas-fir being the species of the largest trees was reflected in this photograph by the large crown at far left. The other conifers to right of this large Douglas-fir were (left to right): blue spruce, Douglas-fir, white fir, and lodgepole pine.

Also abundant in this conifer-dominated forest were smaller trees of Rocky Mountain maple and quaking aspen. Quaking aspen and blue spruce are often associated in more mesic habitats and forest sites in this general area. That relationship was shown at various points in this chapter as in the section devoted to quaking aspen and above in the ponderosa pine-bunchgrass range type.

There was but a very limited herbaceous component in this closed-canopy bottomland forest. Most herbaceous species were in a transition zone between the riparian willow-alder-birch scrub and outer edge of the dense mixed conifer forest. Some of the more showy forbs in this zone were wooly or hairy arnica and common blankeflower.

187. Slyvan lineup- Two photographs of the major species of a montane, mixed conifer bottomland forest along Middle Saint Vrain Creek in the Southern Rocky Mountains. In the first photograph trees were (left to right): blue spruce, Douglas-fir, and lodgepole pine. The second photograph was a closer-in shot of the Colorado blue spruce and Douglas-fir. All three trees were bearing heavy cone crops.

Roosevelt National Forest, Boulder County, Colorado. Early July. Roughly 8000 to 8500 foot elevation.

188. Big bud on a big tree- New, soon-to-open bud on Douglas-fir. This was not a terminal bud composed of apical meristem arising from the terminus or apex of a branch or leader. Instead it a lateral bud arising from intercalary meristem. This intercalary bud will develop into a new or younger branch off of the older branch rather than growing as a node-internode extension of the older branch as would be the case with a terminal bud.

Roosevelt National Forest, Boulder County, Colorado. Early July. Roughly 8000 to 8500 foot elevation.

189. Slyvan maiden- Immature female cone of Douglas-fir. Gymnosperms (members of Gymnospermae) are seed-bearing, but not flowering plants. Instead of having reproductive structures borne in flowers that mature as fruits as in the angiosperms, the gymnosperms have naked seeds that are produced on unisexual (male only; female only) units known as strobili (strobilus, singular) commonly called a cone (either fleshy or woody). The cone or strobilus consist of a series of sporophylls, which are interpreted spore-bearing, modified leaves, arranged on a common, continuous axis (Smith, 1977, ps. 30, 309). Male cones are smaller and are designated as the microsporangiate strobili. Female cones, the larger of the two sexes, are the megasporangiate strobili. Male and female strobili bear microsporphylls and megasporophylls, respectively. These respective cones are sometimes referred to as staminate strobili and carpellate strobili (Holman and Robbins, 1939, ps. 536-544).

Featured in this photograph of the terminus of a Douglas-fir branch was an immature carpellate or megasporangiate strobili or, in simplier terms a female cone. The author found it a fascinating bit of Botany, and not a bad shot of it either. One of the best explanations--along with outstanding line drawings and clear photographs--of sexual reproduction in the Pinaceae of the Gymnospermae was that of Holman and Robbins (1939, ps. 536-554).

Roosevelt National Forest, Boulder County, Colorado. Early July. Roughly 8000 to 8500 foot elevation.

190. Colorado blue- Leaves and nearing-maturity cones of Colorado blue spruce. There is some variation in colortion of needles of blue spruce, but the glaucous, grey-blue coloration seen here is typical.

Roosevelt National Forest, Boulder County, Colorado. Early July. Roughly 8000 to 8500 foot elevation.

191. Maple sample- Leaves and fruits of Rocky Mountain maple (Acer glabrum). Leaves of this Acer species are clearly "mapleish" and at the same time distinctive from other species being broader and smaller than most of the other Acer species.

The fruit of maples have been interpreted alternatively as either as either a schizocarp or samara.. Smith (1977, p. 165) offered the options, "… as either two samaras, separating at maturity, or a samaroid schizocarp, separating into two-winged mericarps at maturity". Smith defined samara as a dry fruit type that is indehiscent with a single seed and an attached conspicuous wing-like appendage (ie.a winged achene) and schizocarp as a dry indehiscent fruit originating from a syncarpous gynoecium splitting at maturity into one-seeded closed segments called mericarps (Smith, 1977, ps. 66, 307).

Roosevelt National Forest, Boulder County, Colorado. Early July.

192. Range forb in an intermediate zone- Wooly or hairy arnica (Arnica mollis) growing in a transition zone between the riparian willow-alder-birch scrub and outer margin of the mixed conifer forest that was featured immediately. This was mesic habitat, but beyond the actual riparian zone. This composite grew beside the composite featured in the next two slides.

Hermann (1966, ps. 291-292) found that palatability of this composite was variable with ratings ranging from poor or even zero through fair to good. .No such mixed reviews as to its simple beauty.

.Middle Saint Verain Creeek, Roosevelt National Forest, Boulder County, Colorado. Early July.

193. Another forb (and another composite)- Common blankeflower (Gaillardia aristata) on a transition zone between a riparian area that supported a willow-alder-birch shrubland and the leading edge of a mixed conifer bottomland forest dominated by Douglas-fir and Colorado blue spruce and with white fir as the associate species.

Although some Gaillardia species are annuals this showy species is a perennial. It is an extraordinary species for use in landscaping with native plants. Hermann (1966, p. 315) stated that the heads of this range forb were "eaten regularly by cattle and sheep…", but that it was more frequently grazed earlier rather than later in the grazing season.

Middle Saint Verain Creeek, Roosevelt National Forest, Boulder County, Colorado. Early July.

194. Still yet another forb- Whole shoot of sulphur-flowered wild-buckwheat (Eriogonum umbellatum) in first slide and details of the inflorescence of this species in second slide. The plant in first photograph was growing on a higher, drier portion of a subalpine mountain meadow in the Southern Rocky Mountains. Closer view of the flower cluster of this species (second slide) was of a robust plant growing on the local ecotone between a willow-alder-birch srubland and outer edge of Douglas-fir-blue spruce-dominated bottomland forest.

Larimer County, Colorado and Roosevelt National Forest, Boulder County, Colorado, respectively. Early July; peak bloom.

195. Willows within- Rocky Mountain willow (Salix monticola) dominated the riparian zone of Middle Saint Verain Creeek that ran through the mesic, montane mixed conifer forest of Douglas-fir, blue spruce, white fir, lodgepole pine, and Rocky Mountain maple described above.From the perspective of Landscape Ecology this stream and its riparian zone was a corridor within a matrix of the Douglas-fir--blue spruce-dominated floodplain forest.

The zone of Rocky Mountain or park willow was a long, narrow willow carr. Most such carrs (including those with cottonwoods along with willow) are considerably wider than was the case for this thin line of park willow.

The diversity of range vegetation within this area was remarkable. A wide zone of Rocky Mountain lodgepole pine (Pinus contorta var.latifolia) forest developed immediately above the general Douglas-fir forest zone.

The second slide offered a better view of a single plant of Rocky Mountain willow. This plant was a female. Catkins on this plant were presented in the next set of two slides.

Roosevelt National Forest, Boulder County, Colorado. Early July; peak bloom.

196. Furry females- Female catkins of Rocky Mountain or park willow. These structures were on the same plant that was shown in the preceding photograph. The fruit of the Salicaceae is a capsule with comose seeds.

Leaf bases seen here were atypical.

Roosevelt National Forest, Boulder County, Colorado. Early July; peak bloom.

197. General exterior views of a widespread type- Rocky Mountain mixed conifer type in the upper montane zone. This distinctive forest range type is a transitional forest community with botanical elements from the ponderosa pine and Douglas-fir forests, Gambel oak scrubland, and pinyon pine-juniper woodland that are all common range types in the Southern Rocky Mountains. It is a species-rich range plant community with various well-developed and prominent layers. Dick-Peddie (1993, ps. 58, 62-64) described this forest community as the White Fir--Douglas-Fir--Ponderosa Pine Series noting that this type constitutes "the most widespread mixed conifer forests in New Mexico".

In these two "photographic dendrograms" all the taller trees were Douglas-fir except the two leftmost tall (adult to near-adult age/size) trees in the first slide which were white fir (Abies concolor). All of the conifer saplings "on the front row" of both photographs were white fir. The trees in lower-right corner and the extreme right margin of first photograph was quaking aspen as were those in distant midground ar right margin of second slide. There were no ponderosa pine visible in these two slides. Also not visible in these photographs was limber pine (Pinus flexilis) although this species was also well-represented in this forest tract as an associate conifer (see slides below). This was a second-growth forest at an elevation of 9400 feet.

There was regeneration of the three dominant and the associate coniferous species. Most of the herbaceous layer of the understorey was made up of the naturalized, perennial, Eurasian pasture grass, smooth brome (Bromus inermis) as shown in the right foreground in the second of these slides. Other grasses included the natives mountain bromegrass (B. ciliatus, probably as varieties genuinus and/or intonsus) and, almost assuredly here and throughout this area, fringed brome (B. canadensis= B. richardsonii= B. ciliatus var. richardsonii). In fact, many authorities lump these simply as B. ciliatus. Individuals of these (this) species were deep in the interior of this stand and had not progressed to anthesis as had the ubiquitous smooth brome. kentucky bluegrass (another naturalized, perennial, Eurasian species) was common especially around edges and in more open sun-lite spots. There were perhaps other Poa species, but at their pre-bloom stage of development this author could not identify them. There were a few plants of what--at earlier phenological development--appeared to be Idaho fescue (Festuca idahoensis). Of course, there were some plants of cheatgrass, but the perennial bromes, including smooth brome, and Kentucky bluegrass "outweighed" cheatgrass by quite a bit. (Incidentially this author chose not to dignify cladistic classification by showing names based on what he viewed as obscure, arbitrary genetic features.)

The herbaceous layer also included Sey's or prickly rose (Rosa acicularis subsp. sayi). In this layer was the low-growing shrub known as low Oregon grape, holly grape, or low holly grape, (Mahonia repens= Berberis repens).

North La Veta Pass (9400 feet), Costillo County, Colorado. Late June (estival aspect). FRES No. 21 (Ponderosa Pine Ecosystem). Mapped as Kuchler- 17 (Ponderosa Pine-Douglas-fir Forest). Some inconsistency here because Kuchler unit 17 is the only unit that that includes both ponderosa pine and Douglas-fir, but K-17 was listed under Ponderosa Pine Forest Ecosystem not Douglas-Fir forest Ecosystem. SAF 210 (Interior Douglas-Fir). White Fir-Douglas-Fir-Ponderosa Pine Series under Upper Montane Coniferous Forest (Dick-Peddie, 1993, ps. 62-64). Rocky Mountain Montane Conifer Forest 122.6, Douglas Fir-White Fir (Mixed Conifer Series) 122.61, Pseudotsuga menziesii-Mixed Conifer Association, 122.613 in Brown et al. 91993, p. 37). Southern Rocky Mountains- Sedimentary Subalpine Forest Ecoregion, 21b (Chapman et al., 2006).

198. On the outside and going inside of a mixed conifer forest- Second-growth upper montane forest of Douglas-fir, white fir, ponderosa pine, limber pine, quaking juniper and common juniper (Juniperus communis) with a well-developed herbaceous layer of smooth brome, mountain brome, fringed brome, Kentucky bluegrass and other Poa species along with some Idaho fescue. Shrubs other than common juniper included the two low-stature species, Sey's or prickly rose and creeping Oregon grape or low holly grape.

The first of these two slides presented another-- though somewhat "closer-to-it"--exterior view (following the two preceding "outside" views) while the second photograph showed the outer edge of this forest range as the photographer moved inside the forest. In the first photograph the taller trees were Douglas-fir except the tallest tree (center, behind Douglas-fir) was a ponderosa pine. There was a pole-sized ponderosa pine with a reddish-brown trunk between two Douglas-fir to right of big ponderosa pine and a ponderosa pine sapling in left-center foreground. Beside (immediately to right of) this ponderosa pine sapling there was quaking aspen. Somewhat larger than the ponderosa pine sapling in foreground were saplings of white fir. Grassy opening in right foreground of this first slide was dominated by smooth brome and Kentucky bluegrass, but immediately behind this native grasses dominated the herbaceous layer.

The second of these photographs featured a plant of common juniper (center foreground) and limber pine (three white-barked trunks in left foreground). Large seedlings to small saplings in foreground were of both Douglas-fir and white fir. All big trees (biggest trunk and one to its left-rear) were Douglas-fir. The well-developed and diverse herbaceous understorey was mostly smooth brome with some Kentucky bluegrass in foreground, but grasses behind that were less phenologically advanced included mountain brome, fringed brome, and Idaho fescue. Present throughout this herbaceous layer though at remarkably low density was cheatgrass.

199. Inside a Rocky Mountain mixed conifer forest- Interior of a upper montane mixed conifer forest range. Major tree species included Douglas-fir, ponderosa pine, white fir with common juniper, limber pine, and quaking aspen as associates. Shrubs were limited with Sey's or prickly rose and low Oregon grape being the two most abundant species in this forest. Deep inside this diverse forest major herbaceous species included mountain and fringed bromegrasses, Idaho fescue, and unidentifiable (at early phenological stages) Poa species. Smooth brome and Kentucky bluegrass were present but secondarily to the native perennial grasseses in the forest interior. Cheatgrass was present but not common.

There were a few forbs, but none were blooming at time of photographs. One of the most abundant forbs (if not the most abundant) was some Astragalus species whose compound leaves were conspicuous in both of these slides. .

Observation: the mixed conifer type of the Sierra Nevada Mountain has been widely recongized and commonly described as, for example, by the Society of American Foresters (Eyre, 1980). Surprisingly, the mixed conifer type of the Rocky Mountains has yet to receive the equivalent recognition even though it clearly exist as a distinctive forest cover type. For instance, this forest community is found throughout forested areas of New Mexico for which it was titled and described as mixed conifer forest by Dick-Peddie (1993, ps. 58, 62-64), New Mexico's reigning student of natural vegetation. Identification and description of forest cover types (Eyre, 1980) and rangeland cover types (Shiflet, 1993) seems as much as anything else in finding authors who will make the effort to write them up. This is probably even more the case for smaller or lesser known cover types.

200. Starting a new forest- A small clearcut of the white fir-Douglas-fir--ponderosa pne mixed conifer type on a ridgeline just behind the second-growth forest shown and described immediately above. The young conifers were pretty much an even mixture of the three climax dominants of Douglas-fir, ponderosa pine, and white fir. The most common and abundant major woody species was Gambel oak (Quercus gambelli). Gambel oak scrubland with associate species of common or alderleaf mountain mahogany (Cercorcarpus mopntanus) and New Mexico locusts (Robinia neomexicana) occurred contiguous with lower elevations of this same tract of forest.

201. Growing low- Holly grape, low holly grape, or low Oregon grape (Mahonia repens) on floor of a mixed montane forest. This interesting plant is a member of the Berberidaceae.

North La Veta Pass, Huerfanoco County Colorado. Late June, peak bloom stage of phenology.

202. A passing rose- Prickly rose (Rosa acicularis subsp sayi) growing in a small gap on on floor of a mixed montane forest. On this particular forest range there were just a few isolated plants of this species that were nowhere abundant enough to provide much by way of browse. Its presence did serve as an indicator of just how botanically rich this forest vegetation was.

North La Veta Pass, Huerfanoco County Colorado. Late June, peak bloom stage of phenology.

203. Rocky Mountain lodgepole pine forest- An exterior view of the Rocky Mountain form of the lodgepole pine range type showing details in structure of vegetation and plants (eg. retention of dead lower limbs on bole). This is the Rocky Mountain lodgepole pine (Pinus contorta var.latifolia). There was one prominent layer of woody plants (mostly shrubs; some, but rare, younger pines) and a less prominent layer of herbaceous species. The woody understorey was dominated by common juniper (Juniperus communis) with dwarf or broom huckleberry (Vaccinum scoparium) and myrtle huckleberry or blueberry (V. myrtillus subsp. oerophilum) as associate shrubs. Most common forbs were heart-shaped arnica (Arnica cordifolia) and one-sided wintergreen (Orthilia secunda). Grasses were absent, but there were a few "runt" individuals of Carex spp.

Apache National Forest, Grand County, Colorado. June. FRES No. 26 (Lodgepole Pine Forest Ecosystem). K-8 (Lodgepole Pine-Subalpine Forest). SAF 218 (Lodgepole Pine). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

204. Rocky Mountain lodgepole pine forest- Interior veiw of the Rocky Mountain form of the lodgepole pine range (forest cover) type. There was a prominent understorey consisting of a woody (mostly shrub) layer and, less prominently, an herbaceous layer. Dominant shrub was common juniper with dwarf or broom huckleberry and myrtle huckleberry of secondary importance. The herbaceous layer (or understorey if one cares to view layer and understorey as synonymous) was mostly forbs with heart-leaved arnica and one-sided wintergreen most common. For practical purposes there were no grasses and very few stunted Carex plants.

Apache National Forest, Grand County, Colorado. June. FRES No. 26 (Lodgepole Pine Forest Ecosytem). K-8 (Lodgepole Pine-Subalpine Forest). SAF 218 (Lodgepole Pine). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

205. Common cedar or common juniper (Juniperus communis)- Common cedar is a widespread understorey shrub in the Rocky Mountains. It is sometimes the understorey dominant in the lodgepole pine cover type. Rocky Mountain National Park, Larimer County, Colorado. August.

206. Leaves and ovulate cones of common juniper- The pollen-producing organs of this dioecious species resemble little pine cones and, from a distance and at first glance, so do the young expanding leaves, at least superficially. Rocky Mountain National Park, Larimer County, Colorado. June.

207. Twig of common juniper- The needles and fleshy seeds on the twig of a female common juniper. The seeds of all the Juniperus species are taken readily by birds which are then major dispersal agents of these conifers. Apache National Forest, Grand County, Colorado. June.

A more thorough treatment (in contrast to the preceding summary) of lodgepole pine forest in the Southern Rocky Mountains was given in the following section.

208. Lower elevational limit- Overall view of the lodgepole pine forest zone at its approximate lowest elevation (about 7500 to 8000 feet) in this area. This shot into the sun on a bright summer morning was a southeast slope. Elevational zones of ponderosa pine and Douglas-fir forest types were below.

Conspicuous shrubs were primarily antelope bitterbursh (Purshia tridentata) with some wax currant (Ribes cereum) and lesser cover of thimbleberry (Rubus parviflora). The dominant herbaceous species was timberline or glaucus bluegrass (Poa glauca subsp. rupicola= P. rupicola).

Details of the interior of the lodgepole pine forest range type were shown below.

Roosevelt National Forest, Larimer County, Colorado. Early July. FRES No. 26 (Lodgepole Pine Forest Ecosytem). K-8 (Lodgepole Pine-Subalpine Forest). SAF 218 (Lodgepole Pine). There should be-- but was not--a Pinus contorta Association and/or Series within (under) the Rocky Mountain Montane Conifer Forest 122.6 in Brown et al. (1998, p. 37). How did they miss this one? Southern Rockies- Crystalline Mid-Elevation Forests Ecoregion, 21c (Chapman et al., 2006).

209. Exterior of a lodgepole pine forest range- Physiogonomy and structure of the Rocky Mountain lodgepole pine range type. An uneven-aged population of lodgepole pine that was at the state of old-growth (though most likely not a virgin forest by any means). This was clearly climax vegetation from standards of species composition and, except for more old and senescing pines, structure. Pine reproduction was limited, but adequate for maintenance of the population. The understorey consisted of at least one shrub layer, two herbaceous layers, and one thallophyte layer (on granite rocks). These layers were shown and described immediately below.

This lodgepole pine forest range was on a general rock outcrop-granitic soil forest site (south to southeast slope) just a few hundred feet above the lower elevational limit of this forest cover type in the Southern Rocky Mountains.

Roosevelt National Forest, Larimer County, Colorado. Early July. Elevation was approximately 8000 feet. FRES No. 26 (Lodgepole Pine Forest Ecosytem). K-8 (Lodgepole Pine-Subalpine Forest). SAF 218 (Lodgepole Pine). There should be-- but was not--a Pinus contorta Association and/or Series within (under) the Rocky Mountain Montane Conifer Forest 122.6 in Brown et al. (1998, p. 37). How did they miss this one? Southern Rockies- Crystalline Mid-Elevation Forests Ecoregion, 21c (Chapman et al., 2006).

210. Now for the interior- Structure and species composition of a Rocky Mountain lodgepole range on a granite rock outcrop in the Southern Rockies. This was an uneven-aged (seedling to senescing adults) population of lodgepole pine with an understorey of at least one shrub layer, two herbaceous layers, and one thallophyte layer (on granite rocks). The major shrub species were antelope bitterbrush, common juniper, bearberry manzanita or kinnikinnick (Arctostaphylos uva-ursi) with dominance and associate rank varying at local scale. There was also cover of wax currant, but this was much less than that of the preceding three species. The dominant herbaceous species was glaucus bluegrass with lanceleaf stonecrop (Sedum lanceolatum), sulphur-flowered wild-buckwheat (Erigonum umbellatum), and sagewort wormwood or field sagewort (Artemisia campestris subsp. caudata) the main forb species.

The darker green mat in center foreground was bearberry manzanita or kinnikinnick. This member of the Ericaceae was also shown in the next two slides which indicated just how abundant this member of the heath family was in the lodgepole forest cover type in this general area.

211. More views on the inside- Two sequential (moving closer-in) shots of the interior of a lodgepole pine forest range on a typical granitic soil-rock outcrop site (south to southeast slope) in the Southern Rocky Mountains.

Most of the darker (or birghter)- green "plant carpet" was bearberry manzanita or kinnikinnick. A large colony of this mat-forming ericaceous shrub as was also shown in the preceding slide.Numerous plants and substantial cover of antelope bitterbrush and common juniper as were cespitose individuals of glaucus bluegrass were also visible in these two photographs. Seedlings, saplings, and small poles of lodgepole pine were distinctly visible in both photographs.

On this forest site of relatively low production potential, lodgepole pine had developed into an uneven-aged forest with comparatively low tree density (low relative density; a relatively sparse cover of lodgepole pine). Reproduction and establishment of interior lodgepole pine was discussed below in the caption beneath two small (young) yet cone-bearing saplings.

212. Plenty of rock- Outcrops of granite adorned the floor of a lodgepole pine forest range in the Southern Rocky Mountains. This was an uneven-aged population of lodgepole pine at or approaching old-growth status with limited (though apparently adequate) pine reproduction. On the shallow soil of this south to southeast slope the adult pines seen here were nearing (or at) their maximum size. Some of the pines in this forest were at the senescing stage and seedlings and saplings were clearly visible.

The dominant (most abundant) forb in this view was lanceleaf stonecrop with glaucus bluegrass, sulphur-flowered wild-buckwheat, and sagewort wormwood or field sagewort also important. Various lichens had colonized the outcropping granite. This thalophytic component was shown in the next set of slides.

213. Range plant community on a rock- Granite outcrop with everything from lichens (featured in the second shot) up through lanceleaf stonecrop and sulfur-flowered wild-buckwheat as most common forbs up through glaucus bluegrass and some unidentifiable (to this author ) Muhlenbergia sp.

214. Slightly different site, but same story- Lodgepole pine forest range on a predominately south slope in the Southern Rocky Mountains. This montane forest vegetation was roughly 500 feet higher in elevation than that featured immediately above. This soil profile was also noticeably deeper, but there was still more than enough granite rock. Like the preceding example, this was most likely climax--certainly, subclimax--vegetation. All of the larger pines were young adults. Though these lodgepole pine were approaching the size of those in the preceding example of this forest cover type the example forest featured here was on a different forest site that had greater potential for tree growth (even though degree of land slope was drastically greater in this example). Thus final adult tree size would be considerably larger on this potentially more productive site (see next slide).

In contrast to the uneven-aged population of lodgeplole pine in the example of this range type presented immediately, the population of this example was even-aged lodgepole pine.Correspondingly, tree density and canopy cover was considerably greater in this lodgepole pine forest. Density and size of individual plants of glaucus bluegrass was also greater, but relative cover of antelope bitterbrush and, especially, of most forb species was much less. There were some scattered plants of wax current (Ribes cereum). (These vegetational features were more obvious in the next two slides.)

On this forest range, forb species were more limited than on the shallower and rockier soil of the preceding example. The dominant forb on this edaphically more favorable site was field sagewort or sagewort wormwood (Artemisia campestris subsp. caudata), but the overall dominant herbaceous species was glaucus bluegrass (and "hale and hearty" specimens at that). Glaucus bluegrass had to share understorey dominance with antelope bitterbrush. This was a sho' 'nough productive forest range with both abundant forage (herbage) and browse crops. Prairie or fringed sagewort (Artemisia frigida) joined its fellow genus member, sagewort wormwood or field sagewort, noted above in the different form of lodgepole pine range vegetation treated here.

Roosevelt National Forest, Larimer County, Colorado. Early July. Elevation was approximately 8500 feet. FRES No. 26 (Lodgepole Pine Forest Ecosytem). K-8 (Lodgepole Pine-Subalpine Forest). SAF 218 (Lodgepole Pine). There should be-- but was not--a Pinus contorta Association and/or Series within (under) the Rocky Mountain Montane Conifer Forest 122.6 in Brown et al. (1998, p. 37). How did they miss this one? Southern Rockies- Crystalline Mid-Elevation Forests Ecoregion, 21c (Chapman et al., 2006).

215. More tree cover, more pine duff, and more bluegrass- An even-aged lodgepole pine forest range with relative high tree density and crown cover in the Southern Rocky Mountains. On more open portions of this forest (including both small parks and local stands of wider tree spacings) the understorey included both a shrub and an herbaceous layer. This was shown in the immediately preceding two photographs. Where tree density and canopy cover were greater (as shown in these two slides) the understorey was mostly limited to a sporadic (interrupted) herbaceous layer comprised almost exclusively of glaucus bluegrass as shown in these two photographs. This was also in contrast to the multilayered understorey on the lodgepole pine forest range detailed in the previous example of lodgepole pine range on a forest site of lower production potential.

Attention was also drawn to the conspicuously greater cover of pine straw (the ground cover layer composed of shed pine needles) on this forest of even-aged trees of higher denser and canopy cover. What, if any, impact greater cover of pine needles had was not known.

Larimer County, Colorado. Early July. Elevation was approximately 8500 feet. FRES No. 26 (Lodgepole Pine Forest Ecosytem). K-8 (Lodgepole Pine-Subalpine Forest). SAF 218 (Lodgepole Pine). There should be-- but was not--a Pinus contorta Association and/or Series within (under) the Rocky Mountain Montane Conifer Forest 122.6 in Brown et al. (1998, p. 37). How did they miss this one? Southern Rockies- Crystalline Mid-Elevation Forests Ecoregion, 21c (Chapman et al., 2006).

216. The very old and large, the very young and small, and those in between- An uneven-aged stand of lodgepole pine on an east slope in the Southern Rocky Mountains. Two old-growth specimens with two seedlings of two sizes at their base and saplings to small poles behind pretty much covered the range in age/size classes. Only tiny new seedlings were missing.

"Lodgepole pine is very intolerant of shade and competition from other plant species" (Burns and Honkala, 1990) with seedlings and other smaller trees typically not thriving under shade. Viewers can see that there was mostly "open sky" in the scene shown here so that younger trees were not subjected to much shade regardless of their age/size classes. In more open forest, especially with widely scttered adult trees, younger lodgepole pines can establish and mature so that uneven-aged lodgepole pine forests sometimes develop. Such was the situation shown here and in the example before the last one above.

The vegetation seen here was a different local forest (and perhaps different forest site) from the two immediately preceding examples. All of three forest locations were within a half-mile radius (or less) of each other. Thie forest shown here was private property in contrast to the public land of a national forest in preceding examples. The present example of lodgepole pine forest had been stocked heavily with horses several years earlier. There was almost no understorey in this lodgepole pine stand. Herbaceous plants were limited to almost exclusively forbs, mostly to white or pale locoweed (Oxytropis sericea) with a respectable showing by the native crucifer, hoary false alyssum (Barteroa incana). The photographer could not help wondering if any horses had been locoed on this wooded range. Maybe that was why it was destocked at time of photograph.

Bark color, patterns, etc. of the two old-growth pines were in stark contrast to each other with the farther tree having smooth bark and the nearer one having furrowed bark. There is considerable variation in bark features among lodgepole pines. Bark color ranges from reddish orange as in these two trees to gray. Bark on most adult lodgepole pine remains relatively smooth, but on some boles the bark is furrowed (as in the foremost trunk here) much like that of ponderosa pine (a source of confusion where the two species occur together). The nearer of these two pines bore the battle scar from a run-in with lightning, an all-too-common atmospheric phenomenon in the Rocky Mountains.Lightning-ignited fires have been a natural part of range ecosystems since there was vegetation to serve as fuel.

217. Early producers- Lodgepole pine is one of the earliest sexually maturing Pinus species in western North America. This precocious species can produce viable seed at ages as young as 5 to 10 years (Harlow et al.,1979, p. 111; Burns and Honkala, 1990), literally baby trees having babies. These two pines were slightly less than five feet tall and both bore cones of ripening seed. Undoubtedly, early seed production is evolutionary adaptation to fire-prone environments (recall the lightning-struck adult lodgepole pine from the preceding photograph). Cones of Pinus contorta var. latifolia are serotinous meaning that cones are retained on trees without opening for more than one year after reaching maturity (Helms, 1998). The serotinous cones of inland or interior lodgepole pine usually open only when there is adequate heat accompanied with a dry atmosphere, conditions most commonly present only with fire or extremely hot weather.

Interior lodgepole pine forests comprise are one of the most pronounced of fire types (cover types adapted to fire and that burn frequently or readily). This commonly results in establishment of dense poplulations of pines of the same age (cohort). These "doghair stands" are often stocked with small, growth-stunted trees (ie. overstocked) which are more prone to crown fires. Natural establishment of even-aged, overstocked lodgepole pine forests is more apt to take place on forest sites that are more favorable for tree establishment rather than on marginal sites on which there can be forests having uneven-aged populations with lower tree density (recall an example of this that was presented above).

The two young cone-bearing lodgepole pines in this photograph were growing on the edge of the even-aged forest shown in the example (two two-slide/caption sets) before the preceding slide.

Roosevelt National Forest, Larimer County, Colorado. Early July.

218. Ripe and breaking off- Terminal portion of a leader of lodgepole pine with mature female (cones). The cones of Rocky Mountain lodgepole pine (Pinus contorta var. latifolia) most commonly break off above their bases so that the bottom part of cones (ie. some of the basal scales) remain attached to the cone-bearing branches. One such instance of such was presented in this photograph.

Lodgepole pine typically has two needles per fascicle. Most needles in this area were about three inches long, at the upper limit of leaf length for this species

Larimer County, Colorado. Early July.

219. Separate-sex cones- Male or pollen cones, microsporangiate strobili, (on two branch terminuses at two left) and female or seed cones, megasporangiate strobili (on branch terminus at right) of Rocky Mountain lodgepole pine.

The details of strobili in the gymnosperms was detailed above when discussing Douglas-fir.

Larimer County, Colorado. Early July.

220. Big girls and little girls- Megasporangiate strobili (female or seed-baearing cones) of Rocky Mountain lodgepole pine on a single leader. The first photograph presented mature cones at left or lower on the branch and immature (pollen-receptive) cones at right or at terminus of branch. The second slide was a view of the terminal portion of this branch so as to feature the immature megasporangiate strobili. This second photograph also showed the the two-needle fascicles of this species.

Larimer County, Colorado. Early July.

221. Now the boy's turn- Male or pollen cones (microsporangiate strobili) of Rocky Muntain lodgepole pine. Also fairly decent shot of needles of this species. This was an early morning ( shortly after sunup) shot after a nice shower the night before.

Larimer County, Colorado. Early July.

222. Grass neighbor- Glaucous or timberline bluegrass (Poa glauca subsp. rupicola= P. rupicola) was the dominant herbaceous species in the understorey of lodgepole pine forest of twn forest sites in the Southern Rocky Mountains. The photographs in this and the next two sets of slides were of glaucous bluegrass growing on ta south slope of relatively deep, granite-derived soil

The first of these two slides showed a larger (presumedly older) plant surrounded by several smaller (younger) plants of glaucous bluegrass along with some small plants of field sagewort (Artemisia campestris subsp. caudata). The second slide presented several still-yet larger plants of glaucous bluegrass with a plant of wax current (Ribes cereum) in the left background. All adult shoots of glaucous bluegrass were bearing panicles.

Roosevelt National Forest, Larimer County, Colorado. Early July.

223. Examples of timberline or glaucous bluegrass- Two large plants of glaucous (timberline) bluegrass at peak bloom served as nice examples of this species which was the dominant herbceous species in understorey of lodgepole pine forest range in the Southern Rocky Mountains. Most panicles of these plants were at immediate post-anthesis stage. Both also had a few sexual shoots from the previous year that remained intact except for shed spikelets. There were a few shoots of field sagewort in the first slide.

Timberline bluegrass is strictly cespitose (ie. tillers only; no stolons or rhizomes).

Roosevelt National Forest, Larimer County, Colorado. Early July.

224. Infloresceances of glaucous or timberline bluegrass- Several examples of panicles on glaucous bluegrass growing on a lodgepole pine forest range. The panicles of this species are relative large and generally described as narrow and somewhat tight or compressed.

Spikelets of this species usually have a conspicuous purple coloration when young, but they take on a pale amber color as they near maturity. Spikelets in three photographs were in milk grain stage and had amber rather than the distinctive purplish color.

Interesting (and practical) point: the Poa species are a "taxonomic challenge" even to the experienced agrostologist. Many bluegrass species closely resemble each other differing only in details some of which are minute or, even trivial. This situation certainly exist for P. glauca and related species. Barkworth et al. (2007, ps. 576-579) described close resemblance of P. glauca, especially P. glauca subsp. rupicola, with several other Poa species especially P. interior and P. nemoralis. According to these workers confusion among Poa taxa is more apt to occur among herbaria specimens with positive identifiction frequently depending on details of features like pubesence, veins, keels, and calluses of lemma and/or palea. P. glauca is extremely variable being "highly polyploid and presumed to be highly apomictic" (Brkworth et al., 2007, p. 577). As if that was not enough, P. glauca hybridizes with other Poa species including the widespread and versatile P. secunda.

Roosevelt National Forest, Larimer County, Colorado. Early July; milk stage of caryopses.

225. Small and showy- Lanceleaf or spearleaf stonecrop (Sedum lanceolatum) in understorey of a Rocky Mountain lodgepole forest range in the Southern Rocky Mountains on a granite rock outcrop forest site. This species was the most abundant forb in the herbaceous layer(s) of this range.

The Crassulacean Acid Metabolism (CAM) photosynthesis pathway was discovered in the Crassulaceae family of which Sedum is a major genus. The habitat of lodgepole forests of this form is a classic CAM-requiring environment: dry soils, short-growing season, frequently limited light, high elevation, severe competition. Light use efficiency is a necessity. Ergo, some of the most successful understorey plants in high elevtion, semiarid, lodgepole pine forest range are those species which evolved traits that use light more effectively and efficiently. Darwin's "survival of the fittest" where survival translates to successful reproduction (survival of the species not necessarily of an individual plant).

Anyway lanceleaf stonecrop is a common and very showy species even if it is a small plant.

Roosevelt National Forest, Larimer County, Colorado. Early July.

226. A memory refresher- Another specimen of common juniper (Juniperus communis). An example of this range conifer was presented earlier, but the one shown in this photograph was growing on the forest range described more recently (the granite rock outcrop forest site) and accompanied by sagewort wormwood or field sagewort (Artemisia campestris subsp. caudata).

Roosevelt National Forest, Larimer County, Colorado. Early July.

227. Colony of fireweed or willowherb (Epilobium augustifolium= Chamaenerion augustifolium)- This member of the evening primrose family (Onagraceae) got it's more common common name from it's adaptation to fire, especially intense forest fires. Fireweed is a pioneer species-- usually the most prominent pioneer-- following fires. This perennial species is found in various regions of North America, but is most widely distributed in the general Rocky Mountain and Pacific Slope Regions.

Fireweed is especially valuable in watershed stability and protection following fires that denude steeply sloping land. It has been regarded as being of fair to good forage (when immature) for small ruminants. The showy, bright-pink inflorescences and graceful leaves impart aesthetic values to this forest and range forb as well.

Fireweed was one of the 200 range plant species included on the Master List for the International Range Plant Identification Contest sponsored by the Society for Range Management. The various editions of North American Range Plants (Stubbendieck et al., 1981, 1982, 1992, etc.) provided complete, yet concise, descriptions of E. augustifolium. Readers were referred to those excellent works. This species was also included in the Range Plant Handbook (Forest Service, 1941, p. W50) and Notes on Western Range Forbs (Hermann, 1966, ps. 185-186).

This robust clump was photographed in the understory of a mature lodgepole pine forest (elevation about 6000 feet) in Yellowstone National Park (and even before the 1988 holocaust). While fireweed is a pioneer and rapidly invades burnt-over ground it still persist into the climax forest as shown in this slide. July.

228. Inflorescence and individual flowers of fireweed or willowherb- This specimen was photographed at peak bloom in the Routt National Forest, Jackson County, Colorado. July.

229. Death cometh on wings- Mixed conifer (lodgepole pine, ponderosa pine, and Douglas-fir, were major conifers; there were a few isolated Engelmann spruce) montane forest in Never Summer Mountains. The forest community shown here was on the Continental Divide or Great Divide at an elevation of about 10,640 feet on a predominately south and west aspect. At this elevation forests of Engelmann spruce and subalpine fir are the typical natural plant community, but at this particular location, and on predominately south and southwestrn slopes, the subalpine Picea-Abies forest cover type developed at higher elevations resulting in a mixed conifer transition forest (= a forest ecotone) between subalpine and montane zone coniferous forests.

The most striking phenomenon (and obvious lesson) from this pair of photographs was death of almost all pines (and the few Engelmann spruce) by feeding of a beetle known variously as mountain pine beetle, pinebark beetles, Black Hills beetle, or Rocky Mountain pine beetle, (Dendroctonus ponderosae). This is a weevil native to North America and its role as a natural herbivore and limiting factor in Pinus populations has been remarked for years, as for instance by Shelford (1963, p. 179). Remaining live conifers in these two photographs were Douglas-fir. There was an almost complete kill of the two pine species and Engelmann spruce. The latter were preyed on by the spruce beetle (Dendroctonus rufipennis). (More of outbreak of the spruce beetle below.)

Herbaceous species were very sparse in the current forest with grasses (mostly Poa and Bromus species) and a few sedges (Carex spp.) making up an interrupted herbaceous layer. These gramnoids could be expected to be released by loss of the former dense canopy of tree crowns.

The most noticable and, more importantly, both the ecological and economic aspects of mountain pine beetle herbivory is the killing of trees in patches--often by the hundreds of acres--rather than as isolated, individual trees. Tree death generally is due to mass colonization and feeding of many weevil larvae inside of their egg and, later, feeding galleries. The female beetle lays groups of eggs inside a gallery she made. Upon hatching the larvae feed on wood in larval galleries mined at right angles to their mother's egg gallery. This mining-feeding activity extends into the phloem tissue and destroys the cambium (at least cambial function) ultimately causing tree death. Trees respond to beetle activity by producing resins to block the galleries. Some species like D. ponderosae are also vectors for the bluestain fungus (Grosmannia clavigera). This saprophytic fungus functions together with mining/feeding action of mountain pine beetle to eventually kill the tree. This ecological relationship of prey tree and insect/pathogen is complex and incompletely understood even after much research (Graham, 1967, Paine et al., 1997). The life cycle of D. ponderosae is one year (one generation annually) in most of the Rocky Mountain System.

Interested readers can find much useful information about the various pine beetle species from a number of sources ranging from standard texts in Forest Entomology, including the standard by Graham and Knight (1965), to reputable, on-line Agricultural Extension publications, including some from Colorado State University and University of Idaho, and materials put out by the US Forest Service. Good sources for the ecological relationship between beetles and fungus include Mitton and Sturgeon (1982) and Schowalter and Filip (1993).

Aggregation pheromones released by adult pinebark beetles attract more adults and soon a tree is under "full attack". Trees are more apt to be attacked under certain conditions including stress due to drought or crowding which is much more likely to occur in "doghair" stands of pine (which, coincidentially, could have been alleviated by natural thinning under low-intensity natural fire or proper prescribed burning.

The central interest from the perspective of the forest plant community and, at larger scale, of forest range ecosystem and landscape is the roles or impacts--both short-term and long-term--of large, severe outbreaks (epidemics) of mountain pine beetle. This native forest insect has influenced forest ecosystems for millenia and in that regard amounts to natural disturbance the same as drought, flood, fire, temperture extremes, avalanches, wind and ice storms, as well as herbivory by other native animals. If conifers like lodgepole and ponderosa pine, Engelmann spruce, and subalpine fir could not co-exist with native insects and pathogen like mountain pine beetle and blue stain fungus these tree species (and their pests) would have been extinct ages ago.

There are almost countless scientific publications devoted to bark beetles and their influence on forests. A readily read synopsis of lodgepole pine and moutain pine beetle included that of Kaufmann et al (2008) which also included an anlysis of the interaction of fire with beetle/fungus-induced mortality. Studies in peer-reviewed periodicals included impact of mountin pine beetle on lodgepole forest succession (Amman, 1976 and regulation of pirmary productivity (Romme et al., 1986).

Nevr Summer Mountains (10,640 feet elevation), Rocky Mountain National Park, Grand County, Colorado. Mid-June (late vernal aspect). FRES No. 21 (Ponderosa Pine Ecosystem). Mapped as Kuchler- 17 (Ponderosa Pine-Douglas-fir Forest). SAF 237 (Interior Ponderosa Pine); no SRM for this pine type per se, but it would be the Southern Rocky Mountain equivalent of SRM 109 or 109 and 110 combination (Ponderosa Pine-Shrubland-Grassland). Southern Rockies- Crystalline Mid-Elevation Forests Ecoregion, 21c (Chapman et al., 2006).

230. Yikes, we're being invaded!- A seral stand of young quaking aspen (Populus tremuloides) being invaded by Engelmann spruce and subalpine fir. This drama of Frederic Clements "dynamic vegetation" was on the boundary between upper montane and subalpine zones. Sucessional replacement of the "quakies" by spruce and spruce is the fate of seral aspen communities at elevations of subalpine forests Beidleman et al., 2000, ps. 14-15).

This process was probably accelerated by extremely heavy browsing by Rocky Mountain elk (Cervus canadensis subsp. nelsoni) which was obviously stressing some of the aspen shoots as was apparent in the second of these two photographs (this second slide was a closer-in version of foreground in the first slide).

Kashian et al. (2007) evaluated dynamics of quaking aspen stands in northcentral Colorado and reported that dominance by various conifers was increasing on over one-third of aspen stands studied. About 15 percent of quaking aspen stands in this area were declining with decline most severe under heavy browsing by elk and/or fire exclusion. Kaye et al. (2005) analyzed impacts of elk browsing and natural succession (invasion) of native conifer species on quaking aspen in Rocky Mountain National Park and adjacent areas. Findings of Kaye et al. (2005) indicated that elk browsing and conifer invasion decreased aspen regeneration (establishment), but did not affect growth rate of established trees (clonal shoots). From studies like these it would be concluded that management to increase quaking aspen abundance should be focused on reproduction (recruitment) of new aspen shoots or, probably less commonly, trees from seed. Otherwise, in absence of natural or prescribed fire and/or with continued heavy browse use by elk, coniferous species like Engelmann spruce and subalpine will continue to replace quaking aspen, at least on those forest sites for which conifers are the potential natural vegetation in absence of fire, outbreaks of bark beetle (Dendroctonus spp.), avlanches, etc.

Rocky Mountain National Park, Larimer County, Colorado. Mid-June (late vernal aspect).FRES No.19 (Aspen-Birch Ecosystem). SRM 411 (Aspen Woodland). SAF 217 (Aspen). Populus tremuloides subclimax Association in Douglas Fir-White Fir (Mixed Conifer) Forest Series of Brown et al.(1998, p. 37). Succession is taking this to: FRES No. 23 (Fir-Spruce Forest Ecosystem). K-14 (Western Spruce-Fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Enlgemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Mid-Elevation Forests Ecoregion, 21c (Chapman et al., 2006).

231. Transition zone forest between Douglas fir on north slope and subalpine fir (locally dominant) and Engelmann spruce-subalpine forest cover types.

Rocky Mountain National Park, Larimer County, Colorado. August. FRES No. 20 (Douglas-fir Ecosystem) and FRES No. 23 (Fir-Spruce Ecosystem) with respective Kuchler units K-11 (Douglas-fir Forest) and K- 19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir) and SAF 210 (Interior Douglas-fir) transition. Ecotone between Englemann Spruce-Alpine Fir Series and Douglas Fir-White Fir (Mixed Conifer) Series of Brown et al. (1998). Southern Rockies-Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

232. Landscape-scale view of Englemann spruce-subalpine fir forest- Appearance of this forest range cover type in early summer at the northern end of the Front Range of the Southern Rocky Mountains. This landscape photograph included the Subalpine and the Alpine life zone as generally used today. In the original life zone scheme (of seven zones) devised by C. Hart Merriam there was no Subalpine. Instead what is commonly called Subalpine in current usage was part or all of Merriam's Canadian and Hudsonian Zones. The Alpine, defined as being above timberline, is the same in both Merriam's and contemporary schemes.

There have also been differences in the use of Southern Rocky Mountains and Central or Middle Rocky Mountains. Fenneman (1931, ps. 92-182 passim) delineated the Southern Rocky Mountain physiographic province as extending through the Laramie Mountains of Wyoming while the Middle Rocky Mountain province included the Yellowstone Plateau, Bighorn Mountains, Tetons, Wasatch Mountains, and Unita Mountains, among others. Shelford (1963, ps. 160-181) divided the Central Rocky Mountains and the Southern Rocky Mountains differently from this. He included the Colorado Rockys as being in the Central division along with the Unita and Wasatch Ranges (Shelford, 1963, p. 160).

Either way this slide showed appearance of the Englemann spruce-subalpine forest cover type growing on the generic subalpine mountain zone inside the Front Range.

Larimer County, Colorado. June. FRES No. 23 (Fir-Spruce Forest Ecosystem). K-14 (Western Spruce-Fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998).Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

233. Englemann spruce-subalpine fir forest- An exterior view of a stand of old-growth Englemann spruce- subalpine fir showing the physiogonomy and structure of this climax forest type. The Society of Amreican Foresters (Wenger, 1984, p. 3) ranked Englemann spruce as Tolerant and subalpine fir as Very Tolerant. The ecological veracity of these ratings was proven in this photograph. Both of these climax dominants were "reproducing in their own shade". The three distinctively green trees of shorter stature in the foreground were young Englemann spruce. Most of the shortest, smallest conifers with the distinctive bluish-green needles were Colorado blue spruce (Picea pungens), a species with tolerance rated as Intermediate. These blue spruce along with some subalpine fir were growing in openings recently created by fallen subalpine fir. Similar colored conifers in the midground between the foreground young trees and the old-growth conifers of the background were subalpine fir of somewhat older age and larger size.

The sparse understorey comprised primarily of Vaccinium species and was not shown in these exterior "shots" of this forest cover type.

Apache National Forest, Grand County, Colorado. June. FRES No.23 (Fir-Spruce Forest Ecosystem). K-14 (Western Spruce-Fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

234. Exterior view of a climax (and old-growth) Englemann spruce and subalpine fir forest in the Front Range of the Southern Rocky Mountains- Composite "shot" of a magnificant Rocky Mountain subalpine forest with a "picture-perfect" display of the species composition. The immense conifer on the far right margin was a subalpine fir as was the younger tree with the conspicuous grayish bark immediately to it's left and the smaller one to it's left. Note that the Very Tolerant subalpine fir were growing under shade of the Englemann spruce (the tall trees in the center and right-center background with the orangish- or reddish-brown trunks). Eyre (1980, p. 86) observed that while these two conifers were generally codominants there were areas and forest sites on which "subalpine fir is the major climax species" while Englemann spruce"is a persistent long-lived seral species". That was at least the partial apparent pattern shown here. Note also crown shape and dead limbs of the Englemann spruce patriarchs. Younger conifers in the left foreground were Englemann spruce indicating again successful regeneration of this Tolerant species. Regeneration of these two species beneath what were obviously old-growth individuals attested to the climax nature of this vegetation.

Understorey composition was primarily Vaccinium and Ribes species, some of which were shown below in this series of slides. Individual plants of Poa and Carex species were present in trace amounts.

Apache National Forest, Grand County, Colorado. June. FRES No. 23 (Fir-Spruce Forest Ecosystem). K-14 (Western Spruce-Fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

235. "Closer in" view of the right side of the preceding photograph- Regeneration of both Englemann spruce (larger of the saplings in right-of-center foreground and in left foreground) and subalpine fir (smallest foreground sapling to immediate left of the "big momma" parent subalpine fir.

Apache National Forest, Grand County, Colorado. June. FRES No. 23 (Fir-Spruce Forest Ecosystem). K-14 (Western Spruce-Fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

236. Colorado blue spruce in a sunlite opening in Englemann spruce-subalpine fir forest- This blue spruce was growing in an opening formed by a fallen subalpine fir in the forest in the three preceding photographs. Blue spruce is rated as Intermediate in tolerance. This species could regenerate in this climax forest only in microhabitats having more light than in the typical understorey environment of this old-growth forest.

Apache National Forest, Grand County, Colorado. June.

237. Colorado blue spruce (Picea pungens)- Branch of the State Tree of Colorado showing pattern of leaves and cones. Apache National Forest, Grand County, Colorado. June.

238. Colorado blue spruce- Details of needles and ovulate (macrosporangiate) cones. Apache National Forest. Grand County, Colorado. June.

The understorey of the Englemann spruce-subalpine fir forest (SAF cover type 206) is often sparse due to the dense shade beneath these tolerant species. Shrubs, especially of the Ericaceae (heath family), are often the dominant or even exclusive species of the spruce-fir climax forest. Forbs of the fir-spruce understorey, though rare, are often prominent and showy. Examples of fir-spruce understorey plants were presented immediately below.

239. Purple fringe (Phacelia sericea)- This dazling member of the Hydrophyllaceae (waterleaf family) is usually "more at home" on sunny habitats like subalpine meadows and talus or scree slopes, but it also finds suitable microhabitats in sunlit openings in the subalpine fir-Englemmann spruce forest. Jackson County, Colorado. June.

240. Globeflower (Trollius albiflorus= T. laxus)- Here is another forb that is more common on subalpine meadows where it can get plenty of light, but it does well along the edges and on open spots within the subalpine fir-Englemann spruce forest. This one was snuggling up next to an Englemann spruce on Larimer Pass (about 10,000 feet elevation). Globeflower is one of numerous species in the Ranunculaceae (buttercup) family found variously throughout the vast Rocky Mountain range from montane to alpine zones. In the buttercup family the individual flowers are borne on a prominent receptacle as shown in the detail photograph of the inflorescence. Jackson County, Colorado. June.

241. Whitestem, smooth or wine gooseberry (Ribes inerme)- Various Ribes species are found thoroughout the forests and adjoining general habitats of North America. Ribes is particularily well represented among the western coniferous forests. Dayton (1931, p. 40) reported that the widely distributed R. inerme displayed here was one of the most common, best known of the western gooseberries. Gooseberry and current are common names for the same or two closely related genera. Some authorities distinguished those plants of common name, gooseberry, as Grossularia species whereas those designated as currents were presented as Ribes species. Some authors have relied on as many as four genera for these plants. Currently, most authors lump all into Ribes. The common distinction between goosebery and current is that the latter bear few or no spines or prickles on their stems. More consistently, currents have jointed pedicels such that their fruit breaks off cleanly from this "stem" whereas the fruit of gooseberries remains attached to this pedicel thus necessitating "snipping" prior to making jams or pies (to which avid gooseberry pickers like your author can redily attest).

The nearly countless publications devoted to native plants (ranging from florae or manuals to field guides) have usually given good descriptions of these interesting shrubs. For their relevance and application to Forestry and Range Management the following classic treatments were recommended: Dayton (1931, p. 40-43) and Forest Service (1940, p. B130-B 133).

242. Flowering leader of whitestem, wine, or smooth gooseberry- This specimen grew adjacent to an Englemann spruce near Larimer Pass. The fruit of Ribes is a berry. It is often a valuable feed source for wildlife species including birds and rodents. Browse from Ribes species is of fair feed value for native ruminants.

An unfortunate turn of events combined with biological relationships led to reduction of Ribes species in regions renowned for the highly valued white pine species (Haploxylon subgenus of Pinus). Ribes serves as intermediate host for the accidentlly introduced white pine blister rust (Cronartium ribicola). In efforts to save the white or soft pines, especially western white pine (Pinus monticola), widespread Ribes eradication programs were conducted in efforts to control or, hopefully, eradicate the white pine blister rust. The effort was unsuccessful and preservation of white pines depends on breeding for rust-resistant genotypes. Fortunately Ribes species were not exterminated in an understandable but misdirected management practice. Ribes species suffer only minor damage when infected by C. rubicola.

Near Larimer Passs, Jackson County, Colorado. June.

243. Interior of a stand of old-growth Englemann spruce- The understorey of a virgin Englemann spruce forest with an exclusive ground layer of red-fruit gooseberry, false gooseberry, or cloudcap current (Ribes montigenum). Several of the Ribes species have "gobs" of common names. This species has proven to be somewhat confusing in that that is regarded as being in the Ribes group known as currents and, despite presence of prickles or spines, not in the gooseberry group that at times has been designated as the separate genus of Gossularia.

Readers should note regeneration of Englemann spruce, a species rated as Tolerant (Wenger, 1984, p. 3). This is an example of a "pure stand" of Englemann spruce. Eyre (1980, p. 86), citing other workers, specified that in the Englemann spruce-subalpine fir forest "pure stands of either species can be found". Such a stand was shown here.

Rocky Mountain National Park, Larimer County, Colorado. June. FRES No. 23 (Fir-Spruce Forest Ecosystem). K-14 (Western Spruce-Fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Enlgemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

244. Englemann spruce-subalpine fir forest on shallow southeast slope- A marginal site for the Englemann spruce-subalpine fir cover type that is in a transition to a limber pine (Pinus flexilis) forest. This shallow site was an example of one kind of a subalpine forest in the Front Range of the Rocky Mountains just below timberline. Fir and spruce trees lacked the massive size of those in slides shown above on sites that were more favorable for development of the fir-spruce subalpine forest. Individuals of limber pine were abundant in this vegetation that was adjacent to a limber pine forest that was presented below. This marginal, transitional forest (ie. combination forest primarily of the Englemann spruce-subalpine fir cover type with components of the limber pine type) had a better developed and more species-rich understorey than many of the subalpine forests in the Southern Rocky Mountains. It was an example of of a Rocky Mountain subalpine forest range of the sort valuable for both livestock and wildlife, especially big game like elk and mule deer.

Rocky Mountain National Park, Larimer County, Colorado. Elevation roughly 10,000 feet. June. FRES No. 23 (Fir-Spruce Forest Ecosystem). K-14 (Western Spruce-Fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir), but with scattered limber pines and conterminous with an old-growth stand of limber pine (SAF 219). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

245. Understorey of Englemann spruce-subalpine fir on a shallow, rocky, southeast slope- Detail of the understorey of the subalpine transition forest shown immediately above. The understorey dominant was grouseberry or broom huckleberry (Vaccinium scoparium). Some species of bluegrass was (or where) present, but none had bloomed or set seed so the author could not identify it (them). One of the more common bluegrasses on such habitat is inland bluegrass (Poa interior). Muttongrass (P. fendleriana) is often locally dominant. The two large clumps of grass were the alien but naturalized orchardgrass (Dactylis glomerata) that served as yet another illustration as how pervasive many of the introduced or agronomic species have become through naturalization. The orchardgrass plant on the left was mostly hidden behind a clump of some species of Carex. Beidleman et al. (2000) described over 60 Carex species growing in Rocky Mountain National Park! Cones of both limber pine and Englemann spruce were visible in the photograph.

Rocky Mountain National Park, Larimer County, Colorado. Elevation about 10,000 feet. June. FRES No. 23 (Fir-Spruce Forest Ecosystem). K-14 (Western Spruce-Fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir).

246. Population of grouseberry, grouse whortleberry, small-leaved huckleberry, dwarf huckleberry, or broom huckleberry (Vaccinium scoparium)- Members of the heath family are some of the most common understorey plants in mountain forests of western North America. Several Vaccinium species are understorey dominants or associates of the Englemann spruce-subalpine fir forest range cover type. V. scoparium is one of these that is valuable as browse for big game animals, sheep, and cattle as well as for it's fruit which is used by small animals like rodents and birds, uncluding upland game birds. Dayton (1931, p. 135) described this species as "… perhaps the most abundant and widespread as well as the smallest and smallest leaved of the western (so-called) huckleberry species".

This sample was in the understorey of the subalpine transition Englemann spruce-subalpine fir forest shown in the preceding two slides (a "sub-sample" of the understorey displayed in the preceding slide).

Rocky Mountain National Park, Larimer County, Colorado. Elevation about 10,000 feet. June.

247. Grouse whortleberry, dwarf huckleberry, broom huckleberry- Detailed view of a plant from the subalpine Rocky Mountain forest understorey shown in the last two slides. The fruit is a small berry that turns red at maturity (the ones seen here were still immature). Rocky Mountain National Park, Larimer, County, Colorado. June.

248. Interior of Engelmann spruce-shrub subalopine forest- In this forest at roughly 9,000-10,000 foot elevation on west side of Continental Divide Engelmann spruce was the dominant tree species while lodgepole pile and quaking aspen were associate tree species and dwarf or small-leaved huckleberry was the dominant shrub (and of the lower layer). This was forest range was a relatively simple natural plant community with only three layers: 1) adult tree or canopy layer, 2) immature tree and, with ragards quaking aspen, short tree or tall shrub comprising a middle woody layer, and 3) low shrub or ground layer.

249. Something to grouse about- The ground or lowest layer (also the third woody layer) of an Engelmann spruce-lodgepole pine-quaking aspen-sublpine forest. This ground or lower shrub layer consisted almost exclusively of Vaccinium scoparium which is known variously as grouseberry or grouse whortleberry or, perhaps as more commonly known among foresters and rangemen, broom, dwarf, or littleleaf huckleberry.

Second photograph showed dung of elk which were heavily browsing the dwarf huckleberry. Dunging is one aspect or category of herbivory. Also presented in this second slide were cones of Engelmann spruce and lodgepole pine.

Rocky Mountain National Park, Grand County, Colorado. Mid-June (late vernal aspect). FRES No. 23 (Fir-Spruce Ecosystem).K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

250. Engelmann spruce- subalpine fir forest range— Rocky Mountain subalpine forest; petran subalpine forest association of Clements. Engelmann spruce (red trunks, foreground); subalpine fir (white bark, background); conspicuous understory forb iswooly ragwort (Senecio atratus).Elevation about 11,000 foot level. Hudsonian life zone of C. Hart Merriam.

Rocky Mountain National Park, Larimer County, Colorado. August, estival aspect. FRES No. 23 (Fir-Spruce Ecosystem).K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

251. Engelmann spruce-subalpine fir forest range type— At an elevation of approximately 11,000 this is less than 1000 feet from timberline so that the understory is a mixture of bluegrasses (Poa spp.), sedges (Carex spp.) and various forbs from the alpine zone and other grasses from the lower life zones such as mountain brome, bearded wheatgrass (Agropyron subsecundum), muttongrass, spike trisetum (Trisetum spicatum), Thurber fescue plus naturalized Eurasian species like timothy and orchardgrass locally abundant.

Rocky Mountain National Park, Larimer County, Colorado. FRES No. 23 (Fir-Spruce Ecosystem).K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

252. Old-growth stand of Engelmann spruce (subalpine fir is a minor component here)- Understory is dominated by shrubs: blueberry or huckleberry (Vaccinium caespitosum, V. myrtillus= V. oreophilum) with bear-berry or kinnikinic (Arctostaphylos uva-ursi) and current (Ribes spp.) as associates. Hudsonian life zone of C. Hart Merriam.

Rocky Mountain National Park, Larimer County, Colorado. Elevation about 10,000 feet. August. FRES No. 23 (Fir-Spruce Ecosystem). K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

253. Finale of a plague- Subalpine Engelmann spruce (dominant)-subalpine fir (associate) forest on west side of Continental divide devestated by outbreak of spruce beetle (Dendroctonus rufipennis ). During the first decade of the Twenty First Century outbreaks of conifer-feeding beetles of various Dendroctonus species occurred across the western half of North America from the west side of the Continental Divide of the Southern Rocky Mountains to British Columbia resulting in deaths of entire populations of Engelmann spruce and subalpine fir as well as lodgepole.

The example shown here was recent death as evidenced by presence of dead needles. Most of the remaining conifers were saplings of Engelmann spruce or subalpine fir (less common were those of lodgepole pine). There were some quaking aspen as well. This was shown to better advantage in the two immediately succeeding slides.

The understorey of this forest tract was shrubby the vast "bulk" of which was dwarfleaf, littleleaf or dwarf huckleberry (see above).

Baker and Veblen (1990) and Veblen et al. (1991) analyzed ecological impacts and plant community changes in Engelmann spruce-subalpine fir due to outbreaks of spruce beetle. Dynamics of spruce-fir subalpine forests were studied and discussed in detail by Aplet et al. (1988). All of these studies were conducted and centered in the Southern rocky Mountains of northcentral Colorado. Simply put, the spruce bark beetle is a native insect that has periodically killed off mass numbers of Engelmann spruce and subalpine fir over extensive regions resulting in elimination of almost all adult trees from spruce-fir subalpine forests. In fact, the Engelmann spruce-subalpine fir forests are greatly reduced over hundreds of thousands of acres for a period of years under these climax forests re-establish through plant succession. Such is the natural dynamics of native vegetation.

Rocky Mountain National Park, Grand County, Colorado. Mid-June (late vernal aspect); approximately 10,000 foot elevation. FRES No. 23 (Fir-Spruce Ecosystem).K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

254. Selective grazing by insect and pathogen (or quakies' revenge)- Feeding, mining, and associated activities of high populations of spruce beetle resulted in death of Engelmann spruce and subalpine fir in this subalpine forest. There were a few lodgepole pines in this forest and most of them had been killed by the pine beetle (this was discussed earlier in this chapter). Some of the smaller conifers had survived (so far), but the main tree species surviving were quaking aspen The first of these two slides presented quaking aspen at scale of this forest stand along with a lodgepole pine (far left margin) that had somehow missed pine beetle attack (apparently anyway). The second slide, at smaller spatial scale, featured trunks of quaking aspen along with those of dead Engelmann spruce and also a seedling of Engelmann spruce (center foreground) as one of the first as the next generation of that species. It will be many a year before this little tree grows to adult size of those killed by spruce beetles.

It was described both above and below how forest succession throughout the Southern Rocky Mountains resulted in replacement of quaking aspen by various coniferous species. This species replacement pattern was commonly aided by heavy elk browsing on quakies. In the instance shown here beetles of Dendroctonus species were a natural disturbance that brought about forest retrogression so that once again quaking aspen was set to regain dominance. That is, for a successional period until Engelmann spruce and subalpine fir as the climax dominant and associtae species, respectively, once again reclaimed this forest range site and reigned supreme.

255. Beetled blessing- Interior of an Engelmann spruce (subalpine fir as associate conifer) subalpine forest with an herbaceous understorey following death of almost every tree by spruce (or spruce bark) beetles. This stand had developed on the upper elevational edge of a wet meadow where drier soils were more favorable for establishment of conifers. The dominant herbaceous species of this understorey was blue wild rye (Elymus glaucus) with bluejoint or Canada reedgrass (Calamagrostis canadensis) as the associate species. There were also some bluegrass species including the naturalized Eurasian Kentucky bluegrass (Poa pratensis) as well as Carex species, especially beaked sedge (C. rostrata). The most common forb was the invasive, naturalized Eurasian weed, common dandelion (Taraxacum officinale), which appeared to be increasing to a critical stage of invasion due to overgrazing by elk. The most abundan native forb was heartleaf arnica (Arnica cordifolia). Rumbaitis del Rio (2006) described a similar herbaceous understorey in an Engelmann spruce-subalpine fir forest following windthrow and salavage logging in the neighboring Routt National Forest.

Impact from beetle-caused death of conifers on herbaceous species remained to be seen. In the short term it seemed likely that the herbaceous species were likely to benefit from increased resources including light, soil moisture, mineral nutreients, etc. These effects was being and will continue to be compounded by heavy elk grazing/broswing. It was undeniable--to this rangeman anyway--that overgrazing by elk had already permitted heavy invasion by the alien common dandelion due to reduced vigor and competitive ability of blue wildrye and bluejoint. Even feces of elk could have some influence on this forest range. Elk dung was widespread throughout this stand and in adjoining stands of subalpine forests (see again above) and wet meadows.

Rocky Mountain National Park, Grand County, Colorado. Mid-June (late vernal aspect); approximaately 10,000 foot elevation. FRES No. 23 (Fir-Spruce Ecosystem).K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

256. Subalpine forest- Physiogonomy and structure of a consociation of subalpine fir on east side of Continental Divide at an elevation of roughly 10,000 foot elevation. There was very little of an understorey other than that of subalpine fir regeneration except around the edges where there were some plants of a Salix species, grouseberry or broom huckleberry, and rock ragwort (Senecio fremontii).

Burns and Honkala (1990) explained that the biological range of subalpine fir includes "the coolest and wettest" of forest habitats in North America. Subalpine fir has been interpreted as Tolerant to Very Tolerant depending on associated conifer species. It is more tolerant than Engelmann spruce, interior Douglas-fir, lodgepole pine, and quaking aspen with which it is associated in the Southern Rocky Mountains so that it and Engelmann spruce form co-dominant climax forests. At higher elevations and on cooler environments like north slopes subalpine fir sometimes forms single-species stands (Burns and Honkala, 1990). The forest shown here was an example of such a "pure" stand.

Rocky Mountain National Park, Larimer County, Colorado. Mid-June (late vernal aspect); roughly 10,000 foot elevation. FRES No. 23 (Fir-Spruce Ecosystem).K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

257. Local stand of subalpine fir- Interior of a stand of subalpine fir approaching state of old-growth. The lack of an understorey was obvious although it was still early in the growing season (snow cover was still widespread as shown in the slides preceding and succeding this one). There was very limited regeneration of alpine fir in this stand. So procede to the next photograph…

258. Proud parents looking down of their progeny- Regeneration of subalpine fir on a road cut just below an old-growth stand that provided seed for this (these) cohort(s). Subalpine fir was found to be a poor seed-producer in the Southern Rocky Mountains with years of good seed crops infrequent. In addition seed viability is generally fair at best (Burns and Honkala, 1990). Furthermore seed germination and seedling establishment is typically best on bare soil (such as roadcuts like the one shown here), but subalpine fir has been found to be less exacting in seedbed requirements than associated spceies being able to germinate and establish seedlings even of thick duff under dense forest canopy (Burns and Honkala, 1990). However seedlings are susceptible to heat injury due to low heat tolerance. Subalpine fir is slow-growing with slow growth rates of roots sometimes being a limiting factor in establishment. This species does reproduce asexually by layering under harsher conditions (eg. timberline), but regeneration by layering is unimportant in mature or closed-canopy forests (Burns and Honkala, 1990).

Sexual reproduction is essential for persistence of this species, but subalpine fir is long-lived such that infrequent reproduction is not a major limiting factor of this Tolerant climax conifer.

Incidentially this was the regeneration scene two days before the summer solstice. Cold-tolerance and, conversely, susceptibility to heat damage of subalpine fir was self-evident.

Some trees of Engelmann spruce were in this stand, but it was essentially a population (= single-species stand) of subalpine fir.

259. Same view the next year- The same population of old-growth subalpine fir and their progeny as shown in the immediately preceding photograph one year later and three weeks later than above. Slow growth rate of subalpine fir was obvious, as was the difference a few weeks advance makes in seasonal progression of the annual growth cycle at this elevation and harsh habitat.

Rocky Mountain National Park, Larimer County, Colorado. Early July (early estival aspect); roughly 10,000 foot elevation. FRES No. 23 (Fir-Spruce Ecosystem).K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

260. Invasion by the climax co-dominants- Edge of local subalpine mountain meadow (subalpine park)-- made up of various bluegrass and bromegrass species along with some caric sedges as predominant herbaceous genera--being invaded by Engelmann spruce and subalpine fir from adjacent mature, climax spruce-fir forest. This subalpine meadow had been disturbed by by mechanical snow removal (to clear a nearby highway) as well as disturbance by northern pocket gopher (Thomomys talpoides) resulting in local patches of bare soil and accelerated soil erosion. This denudation of herbaceous vegetation (removal of meadow turf) served as "new land" available for invasion of the climax co-dominant conifers of an adjacent Engelmann spruce-subalpine fir stand.

The actual potential natural vegetation of this local "park" was not known. Or, stated another way, reason(s) for the "clearing" was unclear. Perhaps this local park was the climax vegetation and the woody invasion an example of range retrogression due to zootic disturbances. Alternatively, previous human activity such as building the highway may have caused loss of the spruce-fir forest as the climax vegetation so that more recent disturbance (perhaps coupled with a local seed source) facilitated re-establishment of climax subalpine forest. Either way, subalpine fir and Engelmann spruce were invading the disturbed subalpine meadow.

Rocky Mountain National Park, Larimer County, Colorado. Mid-June (late vernal aspect); roughly 10,000 foot elevation. Subalpine fir-Engelmann spruce forest was assumed to be the climax vegetation on this range site for purposes of this discussion of forest types in this chapter. FRES No. 23 (Fir-Spruce Ecosystem).K-19 (Spruce-Fir-Douglas-fir Forest). SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

Patch dynamics- The following short (three set) sequence of slides and their captions revealed the dynamic nature of vegetation in a forest gap created with wind fell of a mature Engelmann spruce. This hollow, old-growth individual was claimed by one (or more) gust of high winds that are a nearly every day feature of an Engelmann spruce-subalpine fir forest exuxystem. These few photographs presented the pehnomenon of secondary plant succession in a forest gap, the phenomenon of vegetational recovery in progress (though at a slow rate necessitated by the severity of this high elevation environment.

261. Hole in the canopy- A wind-downed over-ripe (past peak maturity and senescing) Engelmann spruce in an old growth Engelmann spruce-subalpine fir forest resulted in a gap in the otherwise closed crown layer of this range vegetation. With some light reaching the ground surface (understorey) low-growing plant species were able to utilize this precious (limited and essential) resource. Strictly speaking light is one of the abiotic ecological factors that is both a resource and a condition of plant growth. Given the limitedness of light in this forest ecosystem light was most obvious as a resource in development (succession) of this forest community.

The featured recently downed Engelmann spruce was only the latest tree to fall. Note logs of previously fallen adult trees in the second of these two slides (and in the slide of the next caption). It was not known if wind, lightening, or gravity had been the "grim reaper" of earlier downed trees.

Most of the lower community layer was the almost-dwarfish shrub, broom huckleberry or grouse berry (Vaccinum scoparium), with the forb, heartleaf arnica (Arnica cordifolia) the associate species. This lower layer was shown in the next two photographs. Examples of broom huckleberry were presented above.

262. Wind fall- The term "wind fall" was derived from the gathering and use of fallen trees, limbs, branches, etc. for fuel by serf on landed estates during Medieval Times. Villagers and those who lived on estates of the nobility were forbidden from felling of live trees, but people were free to use any dead wood on the ground. Any such fuel so provided by wind or gravity was immediately appropriated by impoverished tenants.

On the forest gap featured in this short section holes in the forest "ceiling" that permitted scarce light to reach the forest floor and rotting logs of fallen Engelmann spruce and subalpine fir that recycled nutrients (fertilized) the soil were a wind fall to whortleberry or broom huckleberry and heartleaf arnica, dominant and associate species of the lowest vegetational layer of this subalpine forest community.

The photographers black shoe in lower left of center provided scale for the low-growing huckleberry and recently emerged heartleaf arnica.

263. Possession of the forest floor, for now- Heartleaf arnica, the locally most abundant species, and broom huckleberry or whortleberry, the overall dominant of this lowest vegetational layer, on the ground surface of a gap formed in an old-growth Engelmann spruce-subalpine fir forest. This was a closer-in view of the forest gap featured and described in the immediately preceding slides and captions.

Although the low-growing shrub and herbaceous composite have the forest floor to themselves at present, the complete coverage of the soil surface by cones of Engelmann spruce (only a few cones of subalpine fir) left no doubt as to which forest citizens would be elected to govern the forest in the very near future. The two climaax dominants of this forest cover type will not have to reach a size of anything near maturity to exclude enough light to result in death of huckleberry and heartleaf arnica seen here and preclude establishment of these two species. In fact, a dense coverage of conifer seedlings will be more effective at excluding light than the lower density and foliar cover of adult trees. (An example of a "dog-hair" stand of subalpine fir seedlings on a roadcut a short distance above this gap was shown above.) Broom huckleberry, heartleaf arnica, and other understorey species will become more plentiful under the mature trees. All of these plant species are components of the climax vegetation.

Heartleaf arnica is a rhizomatous perennial composite that is capable of efficient ground coverage and capture particularily on newly available soil following logging, burning, or natural tree fall as shown here (Hermann (1966, p. 289). One of the most interesting features of Arnica cordifolia is its reproduction solely by apomixis and absence of sexual populations yet with "great variability" resulting from "many slightly different apomictic clones" (Weber, 1990, ps. 72-73). (An example of an adult plant of hertleaf arnica in full bloom was shown below in this chapter.) lBotany and Ecology are such intriguing disciplines. Vegetation is not a dull subject to those blessed with the gifts of awe and wonder.

264. Ecotone between subalpine fir-Englemann spruce forest and limber pine forest (or woodland)- These two photographs were of transitional forest vegetation contiguous with the Englemann spruce-subalpine forest containing considerable cover of limber pine (designated by the author as a "transition" between the two forest cover types or a "combination forest") discussed in the immediatley preceding four slides and the limber pine forest cover type displayed in the following four slides.

Ecotones are transitions or transition zones between two or more different plant communities. There are several forms of ecotones with various kinds of edges or borders. Of course, ecotones are themselves the overlapping borders of adjacent plant communities or vegetation types. Sometimes edges are sharp or discrete. Other forms of ecotones are more duffuse or "blended" over a wider space.

The forest community presented four slides back was one stage or one step in vegetation from Englemann spruce-subalpine fir forest to limber pine woodland. The vegetation seen in these two slides was the next spatial stage in this transition from spruce-fir forest to limber pine forest. This transition was largely a function of elevation and aspect in which limber pine became increasingly more abundant with increasting elevation and progression from a southeastern to a north slope. The forest community now presented was more of a true "mixture" of the two kinds of Rocky Mountain subalpine forest, two kinds of forest range.

It is important that students master the concept of ecotones (vegetational transition zones). Natural vegetation seldom grows in communities as discrete as populations of crops in farm fields or forest plantations.The vegetation displayed here was a good example of a forest ecotone (one in which elevation and slope were determining factors). Ecotones are one of the first examples that shows beginning students that Vegetation Science lacks the accuracy and precision of the physical-chemical sciences and engineering. Vegetation often comes comes in "shades of gray" when resource management demands (or appears to demand) a dichotomous choice.

The first slide showed some young Englemann spruce (eg. the rightmost foreground conifer and several of the spire-topped trees in the background) and common juniper (the small flat plants in the left foreground) intermixed with limber pine. The second slide had a higher proportion of limber pine. These were younger pines with open, widely branching crowns that grew on a south slope. These should be compared (contrasted) to the nearly naked, wind-pruned spires shown below (immediately following the next slide) in a pure limber pine stand on the north slope of this same mountain top. Common juniper was also present (and more conspicuous) in the second slide in the left foreground.

Rocky Mountain National Prk, Larimer County, Colorado. South slope (protected from dessicating, defoliating wind). Elevation about 10,500 feet. June. This ecotonal vegetational did not fit neatly into a simple "black or white" unit, but it was more of the limber pine cover type (SAF 219) whereas the preceding was more of the Englemann spruce-subalpine fir cover type (SAF 206). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

265. Limber pine (Pinus flexilis)- A young limber pine on a southeastern slope protected from severe winter north winds.The shape and well-developed crown of this tree and those in the two preceding slides should be compared to those in the next four slides immediately below. Rocky Mountain National Park, Larimer County, Colorado. June.

266. Limber pine forest or woodland- This was one of the most unique (and picturesque) forest range types found in the Rocky mountain cordillera. A woody plant-dominated community with erie, pole-like skeletons of ancient, wind-pruned limber pines formed an open upperstorey above a mixed understorey composed of a shrub layer and a pronounced herbaceous layer. This vegetation could be interpreted as either a forest or, given the open canopy of these wind-flagged trees, a woodland. Some authors have referred to this community as the limber pine woodland. It was entitled and described as a forest cover type by the Society of American Foresters (Eyre, 1980, ps. 98-99). The prominent shrubby and herbaceous layers of a browsable/grazable understorey made designation of forest range undeniable. Furthermore, it was permanent forest range.

The range component or feature of this vegetation is not limited to certain seral stages or to climax. Rather, there is a range resource throughout the entire sere (successional sequence) of vegetational development. Limber pine woodland is, however, the climax range vegetation on most forest sites on which it developed and persisted as subalpine forest, especially as krumholtz or elfinwood. Shelford (1963, p. 163) concluded: "Bristlecone or limber pine forms an edaphic climax on dry rocky slopes and windswept ridges".

On this north slope immediately below timberline, wind and wind-driven frozen precipitation (ice, sleet, snow) not only flagged the mature trees but killed back recent foliage on the lower brances of limber pine (eg. lower left foreground). Fallen dead trees so littered the ground that it was possible for man and beast to go from one to another without stepping on the ground. The short cool summers retarded microbial decomposition thereby allowing accumulation of limber pine logs among the slow-growing pines of younger generations and the slowly dying patriarchs of earlier cohorts.

The shrub layer was a combination of prostrate, wind-pruned limber pines as well as numerous kinds of willows and Vaccinium species like broom huckleberry or grouse whortleberry (displayed above). The herbaceous layer consisted of various species commonly found on the alpine elevations above the limber pine zone. Some of these were listed in the next caption and presented individually below.

Wind-polished trunks were on both dead and live limber pines (see succeeding slides also). Compare the flagged, almost krumholtz form of these limber pines growing on a north slope to those on the south side of this same mountain top that were shown in the three photographs immediately preceding the limber pine slide above.

Rocky Mountain National Park, Larimer County, Colorado. North slope. Elevation roughly 11,000 feet. June. FRES No. 26 (a complex of lodgepole, limber, bristlecone, and whitebark pine types). K-8 (Lodgepole Pine-Subalpine Forest). SAF 219 (Limber Pine). Bristlecone Pine-Limber Pine Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

267. Limber pine woodland range type- Physiogonomy, structure, and composition of a subalpine limber pine forest or woodland range cover type with well-developed herbaceous, shrub, and tree layers. Herbaceous species included bronze-scale sedge (Carex chalciolepis), blackroot sedge (C. elynoides), interior bluegrass (Poa interior), blackheaded daisy (Erigeron melanocephalus), and alpine clover (Trifolium dasyphyllum). Dominant shrubs were wind-hedged (one form of krumholtz) limber pines and willows of creeping habit due to wind-pruning and/or genetic morphology.

Two features worthy of note: Number one was that wind-scoured whitish bark was on both live pines as well as persistent in small patches on dead pines. Number two was abundant regeneration of limber pine which indicated that this forest or woodland of an Intolerant species was: 1) climax and 2) uneven-aged. Apparently this north slope habitat had at least two major or general impacts. There was more moisture from winter storms and the generally more mesic soil conditions of a north slope environment. There was also more wind which in winter was cold wind (either dry when "northers" came through or wet winds that drove frozen precipitation with force enough to defoliate and "flag" trees). Various combinations of these factors allowed an open canopy and wide spacing of adult limber pines which enabled germination and development of pine seedlings. The combined affect of wind-dessication and wind-driven ice and snow effectively pruned back crowns of mature pines enough to maintain an open forest floor. This in turn allowed reproduction of limber pine and development of a two- or even three-layered understorey. This understorey was comprised of young limber pines and willow species plus with many grasses, grasslike plants, and forbs common on the the alpine ecosystem above and adjoining this limber pine-dominated climax community.

Rocky Mountain National Park, Larimer County, Colorado. North slope. Elevation about 11,000 feet. June. No specific FRES: closest was FRES No. 26 (a complex of lodgepole, limber, bristlecone, and whitebark pine types). K-8 (Lodgepole Pine-Subalpine Forest). SAF 219 (Limber Pine). Bristlecone Pine-Limber Pine Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

268. Composite view of the limber pine forest range type- Structure and composition of a climax subalpine limber pine forest with the three prominent layers of tree, shrub, and herb distinct. Reproduction of limber pine was obvious. This indicated that crown cover and density of adult pines was low enough to permit regeneration of this Intolerant conifer. The uneven-aged structure (= presence of different crown classes) of the limber pine-- the dominant species-- population strongly suggested that this was climax vegetation. It was discussed in the preceding caption how wind had shaped (ie. pruned) the pine crowns thereby allowing establishment of seedlings of the Intolerant limber pine under the "shade" of their parent trees. Wind-burnished bark and dead wood was present on trunks of both living and dead limber pines. Mesic conditions afforded by the north slope on which this vegetation developed was also a requirement for regeneration of the Intolerant dominant.

Plant cover in the foreground was a composite sample of the shrub layer (= woody understorey) throughout this limber pine dominated-vegetation. The leftmost plant, shrub, in the foreground (to the right of the second boulder) was some species of willow that had a creeping habit due to either wind-sculpting and/or genotype (ie. an example of phenotypic plasticity and/or a combination of morphological plasticity and genetically determined shoot form). Willows (species and number of species was not determined) were the associate species of the woody understorey. The dominant of this shrub layer was wind-hedged limber pine (krumholtz or elfinwood form) such that the dominant of the tree or canopy layer, the overstorey, was also the dominant of the woody understorey (ie. limber pine dominated two of the three layers of this plant community). The krumholtz form of limber pine that dominated the shrub layer was represented by the P. flexilis plant(s) adjacent and immediately to the left of the creeping willow (note dead needles due to dessication by wind and wind-driven frozen precipitation).

It was possible that some of the limber pine component of the shrub layer was actually lower limb and branch portions (krumholtz form) of adult pines. Some adult pines of tree form may have developed elfinwood parts below their single, treelike bole that escaped wind-ice pruning and developed under apical dominance. Determination of such phenomenon would require close investigation, perhaps excavation of stumps and upper root systems. Nonetheless, there was unequivocal evidence of abundant sexual reproduction of limber pine in this stand.

Dominant species of the lowest layer of vascular plants, the herbaceous layer or understorey, was not obvious but was apparently blackroot sedge. Other common herb species were bronze-scale sedge, interior bluegrass (and other bluegrass species that were not blooming and could not be identified), composites like blackheaded daisy, and alpine clover. These herbaceous species were some of those most common on the alpine turfs and fell fields conterminous with the limber pine forest. A representative patch of this often turf-like herbaceous understorey was obvious immediately behind the krumholtz willow and limber pine in the foreground.

It was again remarked this climax plant community was permanent forest range: a grazable/browsable understorey was a component of this vegetation throughout the successional sequence of the sere and was not limited to seral stages prior to climax or canopy closure (whichever came first). Obviously the crown classes did not include the point of canopy closure. There was adequate light for understorey development and persistence throughout the entire spatial array of vegetation development.

Rocky Mountain National Park, Larimer County, Colorado. North slope. About 11,000 foot elevation. June. No specific FRES: closest was FRES No. 26 (a complex of lodgepole, limber, bristlecone, and whitebrk pine). K-8 (Lodgepole Pine-Subalpine Forest). SAF 219 (Limber Pine). Bristlecone Pine-Limber Pine Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

269. Limber pine forest cover type- Climax limber pine forest or woodland (depending on how crown canopy, aerial cover, tree spacing, and density, is interpreted) with a permanent grazable/browsable understorey. Structure and composition of this permanent forest range was evident in this slide. The were three prominent layers: tree, shrubby, and herbaceous. The herbaceous layer consisted of grass, grasslike plant, and forb species abundant of the alpine range ecosystem conterminous with this subalpine limber pine forest. Herb species included blackroot sedge (closest thing to the herbaceous dominant), bronze-scale sedge, bluegrass species, composites, and alpine clover.

The shrub layer was dominated by the wind-sculpted elfinwood form of limber pine with species of willow as associates. Interesting, the same species-- limber pine-- dominated two of the three layers of vascular plants in this vegetation. It was certainly the limber pine cover type.

Death of pine leaves by dessication on this wind-swept north slope was pronounced. Accumulation of dead and down timber of limber pine was due to slow rates of decomposition on this cold site. Even though the north slope aspect created a mesic site much of the annual precipitation comes as snow (or ice) when temperatures are too low for rapid rotting of wood and at this elevation the warm season is too short for much microbial reduction.

Rocky Mountain National Park, Larimer County, Colorado. North slope. Elevation approximately 11,000 feet. June. No specific FRES: closest was FRES No. 26 (a complex of lodgepole, limber, bristlecone, and whitebark pine types). K-8 (Lodgepole Pine-Subalpine Forest). SAF 219 (Limber Pine). Bristlecone Pine-Limber Pine Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

Prominent herbaceous species in this limber pine forest included:

270. Blackroot sedge (Carex elynoides)- This cespitose sedge appeared to be the most common plant in the herbaceous layer of the limber pine woodland presented in the preceding five slides. The carices traditionally have not been accorded coverage like that of the more economically important grasses (or trees), but some outstanding references are available. For C. elynoides refer to Hermann (1970, ps. 204-205) and Hurd et al. (1998, ps. 108-109).

Rocky Mountain National Park, Larimer County, Colorado. North slope in understorey of limber pine woodland; roughly 11,000 foot elevation. June.

271. Bronze-edge sedge (Carex chalciolepis = C. heteroneura var. cahlciolepis )- This is a showy sedge (by sedge standards). It was both abundant and prominent in the understorey of the tract of limber pine woodland discussed above. Standard reference, including forage value, for this Carex species was Hermann (1970, p. 313-314).

Rocky Mountain National Park, Larimer County, Colorado. North slope in understorey of limber pine at about 11,000 feet. June.

272. Inland bluegrass (Poa interior)- This was the most obvious grass in the herbaceous understorey of the limber pine forest range. It was the only member of the Gramineae that was in flower or seed so as to be positively identified. Rocky Mountain National Park, Larimer County, Colorado. North slope at about 11,000 foot elevation. June.

273. Blackheaded daisy (Erigerion melanocephalus)- There are several species of Compositae in the alpine ecosystem and adjoining subalpine communities such as the limber pine forest. Blackheaded daisy was the most common forb in the tract of limber pine woodland presented above. Erigerion species are more commonly known as fleabanes. This species was not discussed in Notes on Western Range Forbs (Hermann, 1966), but can be found in standard references including field guides and florae.

Rocky Mountain, Larimer County, Colorado. North slope limber pine climax forest; elevation roughly 11,000 foot. June.

274. Alpine clover (Trifolium dsayphyllum)- There are three, perhaps, four species (depending on personal view) of Trifolium species in the alpine turf and fellfield types and adjoining range types (eg. limber pine forest range) that closely resemble each other. Alpine clover is common, even locally dominant, in all of these high elevation plant communities. The examples shown here grew in the understorey of the limber pine forest tract presented above.

Rocky Mountain Ntional Park, Larimer County, Colorado. North slope forest understorey at approximately 11,000 feet. June.

275. Timberline— The ecotone or transition zone between the Engelmann spruce-subalpine fir forest and alpine ecosystems.This is the last toe-hold of these conifers as the tree growth form at the edge of krumholtz or elfinwood growth form. Understory has herbs of both ecosystems (vegetation types). Wooly ragwort is conspicuous; grasses present are those listed two slides back. Migration of conifers into a subalpine meadow. Rocky Mountain National Park, Colorado.Elevation is between 11,000 and 12,000 feet. On the border between two life zones: the Hudsonian and the Alpine. August. As discussed below under the Alpine range types, the Society for Range Management (1994) did not offer a number or description for the Rocky Mountain alpine ecosystem. SRM rangeland cover type 410 is "as close as it gets"; SAF forest cover type 206 for the spruce-fir zone. Two major ecosystems: FRES No. 23 (Fir-Spruce Ecosystem) and FRES No.44 (Alpine Ecosystem) with respective Kuchler equivalents K-19 (Spruce-Fir-Douglas-fir Forest) and K-45 (Alpine Meadows and Barren).Spruce Elfinwood Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

276. Quaking Aspen (Populus tremuloides) grove— the tree growth form of "quakies" producing an obvious forest type with an understory that is almost exclusively forbs, including poisonous ones. Note the infamous false-hellebore or corn lily (Veratrum californicum) which causes the cyclops lamb tetrogenicity when eaten by ewes on the fourteenth day of gestation. The toxic western larkspur (Delphinum occidentale) is also common , but so are valuable forage forbs like Richardson's geranium (Geranium richardsonii).Routt National Forest, Jackson County, Colorado. July, peak estival aspect.

There are no FRES or Kuchler Numbers for this cover type. FRES No. 19 (Aspen-Birch Ecosystem) would be a rough guide, but all the Kuchler equivalents therein are seral stages whereas quaking aspen does on some sites, as illustrated here, form populations that are not seral. On other sites quakies are clearly seral to spruce and fir climaxes such as those shown in the four preceeding slides. In cases of the latter, quaking aspen can exist as a fire-maintained type. The quaking aspen parkland as representedhere covers vast acreages in parts of Canada and the inland Northwest of the United States where it is scattered throughout or among grassland communities often as a boundary between grassland and the boreal coniferous forest or, at lower latitudes, Douglas-fir and pines like lodgepole and ponderosa. Quakies comprising most of these more northern aspen groves are shrubs. The stature and growth form of those quakies qualifies as a shrubland cover type and could as correctly be shown under the shrublands section. All quaking aspen types were placed here for convenience and to avoid confusion. SRM 411 (Aspen Woodland).SAF 217 (Aspen). Populus tremuloides subclimax Association in ecotone between Douglas Fir-White Fir (Mixed Conifer) Series and Yellow Pine Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

277. Interior of the quaking aspen grove shown in the preceding slide- Note abundance of false-hellebore and western larkspur. Note also bark-browsing by elk (Cervus elaphus= C. canadensis) as for example the scar and blackened bark on the largest trunk in center but not overbrowsing that prevents the visible regeneration of aspen. Routt National Forest (astraddle the Continental Divide), Jackson County, Colorado. July. No FRES or K- designations. SRM 411 (Aspen Woodland); SAF 217 (Aspen). Populus tremuloides subclimax Association in ecotone between Douglas Fir-White Fir (Mixed Conifer) Series and Yellow Pine Series of Brown et al. (1998). Southern Rockies- Crystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).

278. Quaking aspen grove- This is another example of a grove of quakies showing the physiogonomy and structure of a relatively young stand. It was growing just above a small stream at the base of a large hillside covered with a mountain big sagebrush (Artemisia tridentata subsp.or variety vaseyana) shrub steppe. Species in the aspen understorey were primarily those of the sagebrush shrub steppe including mountain big sagebrush several individuals of which were growing in the center foreground at the edge of the grove.

Grand County, Colorado. June. It was explained in the first caption of this series that there was no specific FRES or Kuchler Number for quaking aspen. FRES No.19 (Aspen-Birch Ecosystem) was as close as possible. SRM 411 (Aspen Woodland). SAF 217 (Aspen). Populus tremuloides subclimax Association in Douglas Fir-White Fir (Mixed Conifer) Series of Brown et al. (1998). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

279. Interior of quaking aspen grove- Inside the grove of quaking aspen shown in the preceding slide. Species in the herbaceous understorey included timber oatgrass (Danthonia intermedia), Idaho fescue (Festuca idahoensis), cheatgrass (Bromus tectorum), Sandberg bluegrass (Poa secunda= P. sandbergii), and an unidentified species of lupine, all of which were at prebloom stage. Growing immediately adjacent to the boundary of the grove and adjoining mountainbig sagebrush steppe (ie. along the edge of the two range cover types) was squirreltail bottlebrush (Sitanion hystrix) and the prominent forb, false helleborne. The latter was introduced in the first slides of this series.

Grand County, Colorado. June. Approximate FRES No.19 (Aspen-Brich Ecosystem). SRM 411 (Aspen Woodland). SAF 217 (Aspen). Populus tremuloides subclimax Association in Douglas Fir-White Fir (Mixed Conifer) Series of Brown et al. (1998). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

In the author's observations (emperical not experimental) the understorey of quaking aspen groves varies greatly, even over remarkably short distances, depending on the species in adjacent or proximate plant communities where the surrounding vegetation is the dominant cover type of that general location. This observation obtains for scattered groves of quaking aspen in a matrix of other range type(s) and not where aspen is the general dominant range type for that location (not for instance where aspen parkland covers vast expanses and is the regional climax, the climatic climax at regional scale). Where aspen groves occur at elevations at or just above the ponderosa pine zone the aspen understorey tends to have the less mesic grasses and forbs of the pine forest whereas when aspen grows at higher elevations up into the Englemann spruce-subalpine fir forest the aspen grove understorey has the more mesic and shade-tolerant herbaceous species of the latter forest. (Or, as shown immediately below, quaking aspen is seral to the spruce-fir forest.). In the preceding example where the small aspen stand grew in a matrix of mountain big sagebrush steppe the dominant understorey species were those of the shrub steppe.

The successional status of quaking aspen for a given habitat (ie. on a specific sere) may be even more important in determining species composition and structure of the understorey. Aspen groves (or even the larger spatial scale of aspen woodland) might have a different understorey depending on whether aspen is a seral or the terminal stage of plant succession on a given range site or habitat type. An example was shown in the next slide which can be compared with those of other groves in this series.

An excellent source on maintenance of quaking aspen is the symposium proceedings compiled by Shepperd et al. (2001).

280. Stand of quaking aspen being invaded by Englemann spruce and Colorado blue spruce- The successional status of quaking aspen is very much site-dependent, a fact that has often been overlooked when arguments have arisen where aspen was replaced by other species. Yes, indeed sometimes such replacement was due to improper management as when overbrowsing by livestock or big game resulted in loss of quakies and their replacement by herbaceous species or where underburning (or complete fire exclusion) allowed less fire-adapted shrubs and trees to invade stands and ultimately replace the aspen.

Ecologists may never understand completely the dynamics of such vegetational development. It is known that quaking aspen is the potential natural vegetation or climax where it forms extensive parklands in more northern regions. At the other end of plant succession aspen is sometimes a pioneer species that colonizes disturbed areas. This latter pehnomenon would apply to secondary not primary succession. It is also known that on some habitats quakies are seral to coniferous forests. One of the best known examples of this latter successional pattern is where (again, on some sites) quaking aspen is seral to the climax Englemann spruce-subalpine fir forest. That condition was shown in this photograph.

An old stand of quaking aspen was being invaded mostly by Englemann spruce and Colorado blue spruce with some lodgepole pine (Pinus contorta var. latifolia) and even a few limber pine (Pinus flexilis) also appearing to become established. (The pine saplings were too small to be relicts of the same age as the aspen.) Quaking aspen (along with cottonwoods) was ranked by the Society of American Foresters as Very Intolerant, the least tolerant of any western hardwood, whereas Englemann spruce was ranked as Tolerant and subalpine fir was Very Tolerant (Wenger, 1984, ps. 3-4). Where the site potential will support spruce-fir forest it is inevitable that these species will eventually replace the quakies, unless of course repeated disturbances like fire and avalanches prevent progression of plant succession.

This forest vegetation was on an east slope and there was a spring or hillside seepage at the lower edge of the forest where it was advancing downslope and invading a wet meadow. This forest site, especially the wettest microsite, was extremely favorable to blue spruce.

The two young conifers in the far right foreground were Englemann spruce and the conifers in the background were the famed Colorado blue spruce. No subalpine fir were found and there were no adult subalpine fir trees present within the immediate vicinity. Blue spruce were more common downslope and Englemann spruce more abundant upslope from this forest stand, as was the limber pine which grew in association with the spruce-fir forest at higher elevations as the spruce and fir gave way to limber forests.

Readers can find a straightforward discussion of the natural history of quaking aspen groves in Mutel and Emerick (1992, ps. 141-151). These authors presented a very readable account of this community (both plant and animal) that will help students understand basic structure, composition, and dynamics of this forest or shrubland type.

Rocky Mountain National Park, Larimer County, Colorado. Approximate FRES No.19 (Aspen-Brich Ecosystem). SRM 411 (Aspen Woodland). SAF 217 (Aspen). Populus tremuloides subclimax Association in Douglas Fir-White Fir (Mixed Conifer) Series of Brown et al. (1998). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

Succesional sequel- The following four slide-caption set sequence was of the same stand of quaking aspen being invaded by Engelmann and Colorado blue spruce as shown immediately above-- except sixteen years later. This sequential set began with the same photopoint as shown in the preceding photograph.

281. Some of us grew; some of us only grew older- The same photgraphic point of a grove of quaking aspen being invaded by Engelmann and Colorado blue spruce as shown above-- sixteen years earlier. Oviously the conifers have grown (some of them considerably) while the existing aspen shoots have senesced (slowily dying following shoot maturity) and only a few new aspen shoots were produced (ie. senescence combined with lack of regeneration). This asexual reproduction of the "quakies" was limited to the perimeter of the grove so that there was some incremental expansion of aspen around outer edges while conifers were "banishing" (overwhelming) the senescing aspen shoots. With on-going plant succession conifers (primarily Colorado blue spruce) were in the process of "ousting" the quakies" and laying claim to the sere, specifically the interior of the aspen grove. Even previously existing lodgepole pine had grown and new seedlings and saplings of lodgepole pine had invaded (established).

Growth rate of all these trees had been relatively slow in the continental climate of the Southern Rocky Mountains with long, cold winters and short, cool summers. This slow growth of all tree species can be easily ascertained by comparison of this photograph with the one of sixteen years earlier seen immediately above. Nonetheless, increase in size of trees (height, diameter breast height, canopy cover) was visibly greater in conifers, especially blue spruce, than in quaking aspen. Furthermore (and ultimately more important) was the greater rate of regeneration of conifers relative to aspen, the latter of which was nearly nil. It was obvious what the successional outcome would be over time, the time period of forest development. That is, of course, unless some other factor(s) changed the trajectory of forest community change (see below).

Quaking aspen, as was detailed above, is a clonal organism. This aspen grove was mostly--if not exclusively-- one tree (one clone= one genetic individual, one genotype) of numerous shoots. The "trunk" of the tree is a rhizomatous system with "trees" in the grove being shoots ("limbs" or "branches") off of the underground "trunk". In absence of a regenerating "disturbance" such as fire or avalanche the aging aspen clone became a maturing (and slowly dying) grove of old "trunks" (shoots).

Meanwhile, individuals of the two coniferous species (single trees of a genotype, a unique genetic individual conifer) continued to grow and increase in size and crown cover (trees got taller with larger crowns of bigger and more branches with more needles), plus with some sexual reproduction (seed production). In the sixteen year interim between time of forest vegetation shown in the preceding photograaph and that seen in this (and subsequent) photographs Colorado blue spruce had "outdistanced" Engelmann spruce and had come to dominant the developing forest. More lodgepole pines had established (invaded) in the perimeter of the advancing aspen grove.

As new shoots of "quakies" grow and mature around the perimeter of the grove, Colorado blue spruce and Engelmann spruce along with loegepole pine will invade that land and displace (replace) aspen through plant succession.That is, this successional sequence, this profression of plant succession and conifer forest development, would continue if some other factor or phenomenon did not interfere. More on that phenomenon below …

Rocky Mountain National Park, Larimer County, Colorado. Early July (earrly estival aspect). Formerly this forest vegetation fit the following approximate units: FRES No.19 (Aspen-Brich Ecosystem), SRM 411 (Aspen Woodland), SAF 217 (Aspen),. Populus tremuloides subclimax Association in Douglas Fir-White Fir (Mixed Conifer) Series of Brown et al. (1998). Sixteen years later the forest had undergone progression (plant succession) on the sere to the extent that the range vegetation now more closely fit the following units: FRES No. 23 (Fir-Spruce Ecosystem). K-19 (Spruce-Fir-Douglas-fir Forest). SAF 216 (Blue Spruce) locally at elevation just below the zone of SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

282. Coming on strong and slowing going out- Exterior (general) and interior views--first and second photographs, respectively--of a grove of quaking aspen, the adult shoots of which were senescing faster than reproduction (which would have mostly asexual) of new shoots necessary to replace mature ones and maintain the population. Concurrently, Colorado blue spruce was on tract to become dominant (with some Engelmann spruce and lodgepole pine as associate species) as existing trees of these species advanced in age, size and relative canopy cover as well as having sexual regeneration so as to expand their presence and cover into parts of the grove previously unoccupied by them.

This upper montane, east-slope forest was moving via plant succession from an aspen grove to a conifer forest dominated by blue spruce. There had been some regeneration of aspen--as seen in foreground of first photograph--on the outer margin of the grove, but there had been essentially no (certainly very litttle net) regeneration of aspen in the interior of the grove. Meanwhile, the conifers (again, mostly Colorado blue spruce) were continuing to grown, reproduce, and increase their relative canopy cover throughout this forest community including at the margin or outer extremity of the forest as seen clearly in the second photograph. Conifers at the exterior of this forest (second photograph) where it was advancing into (invading) a wet meadow ranged from larger seedlings to saplings and included both blue spruce and lodgepole pine. New aspens (clonal shoots or sexual seedlings/saplings) were absent from the leading edge. The "quakies" have had it--unless something changes.

Rocky Mountain National Park, Larimer County, Colorado. Early July (earrly estival aspect). FRES No. 23 (Fir-Spruce Ecosystem). K-19 (Spruce-Fir-Douglas-fir Forest). SAF 216 (Blue Spruce) locally at elevation just below the zone of SAF 206 (Englemann Spruce-Subalpine Fir). Englemann Spruce-Alpine Fir Series of Brown et al. (1998). Southern Rockies- Sedimentary Subalpine Forests Ecoregion, 21e (Chapman et al., 2006).

283. Overwhelmed- Adult Colorado blue spruce grrew up through quaking aspen which senesced and died out (perhaps partially reduced due to competition with the conifers) so that the previus aspen grove (SAF cover type 217 SRM cover type 411) was converted through plant succession to blue spruce fores (SAF cover type 216).

This was a local stand in the larger aspen grove shown above. It was the part of tht grove that had moved farthest on this sere (forest site) toward coniferous forest and away from the previous advanced seral stage of the quaking aspen cover type. A spring or water seepage characterized and distinguished this local habitat of the sere (most precisely it was a wet hill slope microsite) so that it was the wettest part of the (former) aspen grove.

Eyre (1980, ps. 95-96) interpreted the blue spruce forest cover type as "subclimax" that typically was replaced (succeeded) by the Engelmann spruce-subalpine fir cover type.It was further explained that the blue spruce type (SAF 216) was a relatively restricted type that was present as climax only along streams, where forest edges met meadows, on "low moist soils", or "subirrigated slopes", The latter three of these conditions existed on the land on which this stand of maturing blue spruce had developed. Furthermore, this forest vegetation was on an east slope so as to be more mesic to begin with.

It was predictable that successional advance from quaking aspen to blue spruce-dominated coniferous forest would be most rapid on this wet hillside. Wet edaphic conditions probably also explained why blue spruce was dominant instead of Engelmann spruce (or even subalpine fir) which dominated higher elevation forests immediately above this developing forest.

284. Come and go, give and take- Another view of the advancing margin of a mesic, high montane forest on which conifers (namely Colorado blue and Engelmann spruce with some lodgepole pine) were replacing quaking aspen with the progression of plant succession (ie. aspen is seral to a blue spruce climax or subclimax on this forest site). This forest was on an east slope and invading a wet meadow.

Immediately obvious was the absence of any quaking aspen reproduction (neither asexual or clonal shoots nor new trees as seedlings or saplings) accompanied by abundant reproduction of both Colorado blue and lodgepole pine (foreground). Higher up on this east slope Engelmann spruce of sapling and small pole sizes were abundant.

Engelmann spruce and lodgepole pine were also in trouble. In spite of regeneration of these two conifers a widespread catastrophic outbreak of spruce (or spruce bark) and pine (pine bark) beetles (Dendroctonus species) had decimated populations of Engelmann spruce and lodgepole pine throughout this region. Plus, bark beetles were continuing to kill many and, in local areas, most of the few remaining trees. Some beetle-killed, pole-size Engelmann spruce were visible in this photograph (midground). These Dendroctonus species are native insects. For millenia bark beetles have functioned as natural disturbances that displaced climax conifers and set secondary plant succession into motion. Impact of the Dendroctonus decimation on Engelmann spruce-subalpine fir, lodgepole pine, and ponderosa pine climax forests in this area were described earlier in this chapter.

Bark beetle herbivory--again, a natural disturbance--was a phenomenon that was favorable to the seral quaking aspen. Examples of this were shown above. Aspen were still "not out of the woods", however, because excessive defoliation, overbrowsing by elk had been a major factor in preventing reproduction (sexual and asexual) of quaking aspen along the advancing edge of this forest. The result was that woody invasion of the wet meadow downslope from the established forest had been limited to that by conifers. The natural pattern of forest succession was interrupted by elk overbrowsing so that blue spruce, Engelmann spruce, and lodgepole pine were establishing without having to replace aspen (and perhaps without facilitation by this seral species).

Another sure sign of heavy browsing by elk were the many glaring scars on aspen trunks resulting from "barking" (bark feeding) by this generally grass-preferring cervid. This showed up well on this photograph. Close-up photographs of bark scars were presented in the immediately two succeeding slides.

Herbivory by bark beetles had slowed the advance (and were still in process of slowing) invasion of the wet meadow except Colorado blue spruce had yet to be impacted by Dendroctonus species. Smaller trees (seedlings and saplings) of affected conifer species typically are not fed on by bark beetles. Hence, conifers of these age/size classes were still alive at advancing (invading) edge of this forest (foregroung of photograph). Would bark beetle populations subside to normal level so that these young trees would reach adulthood? Would the wet meadow ecosystem survive or would it become a coniferous forest (or maybe woodland or savanna)? Only God knows and time alone will tell.

285. Elk-carved totem pole- Bark scars on trunks of adult quaking aspen at the edge of a senescing aspen grove that had expanded down an east slope and invaded a wet meadow. Elk prefer herbaceous plants, especially grasses and grasslike plants, but they are opportunistic and diverse feeders that readily consume browse. Quaking aspen are a preferred elk browse plant. Leaves, buds, and young shoots appear to be the more preferred parts of aspen, but elk readily feed on aspen bark. Bark-feeding has appeared to be more widespread under conditions of high stocking rates of elk, especially at levels regarded as overbrowsing.

Feeding on new clonal shoots by elk had unquestionably retarded--in fact, at this location elk overbrowsing had completely precluded--aspen regeneration. In combination with ample reproduction of blue spruce, lodgepole pine, and, at lower rates, Engelmann spruce this grove of quaking aspen was moving rapidly via plant succession to a blue spruce forest. (This was explained immediately above.)

The small shrubs in these two photographs (especially the first slide) were alder (Alnus incana), a riparian species that was locally abundant in the wet meadow at the edge of and immediately below this aspen grove that was becoming a forest dominated by Colorado blue spruce. The yellow-flowered forb on ground layer was heartleaf arnica.

Commonly, quaking aspen quickly replaces bark removed by browsing elk. That was evident from these two photographs. Extremely "deep browsing" by elk below bark and into cambium results in much slower healing wounds. Two such wounds were visible in the shoot shown in the first of these slides. Also noteworthy in this slide was the small snag of a sprout (offshoot, clonal shoot) produced by this adult, parent shoot and promptly killed by elk overbrowsing. Again, an overpopulation of elk and consequent overbrowsing had virtually stopped aspen regeneration.

The disgrace of this unacceptable management was on a national park! Rocky Mountain National Park should be opened to sport hunting or else culling by government employees such as personnel of Animal Damage Control in the United States Department of Agriculture. Establishment of native predators, especially the grey wolf (Canis lupus), might eventually result in reduction of elk numbers in Rocky Mountain National Park. If and until such natural population control occurs human intervention by hunting (culling) is absolutely essential for proper use of range resource and the general Southern Rocky Mountain ecosystem.

Degradation of quaking aspen range by elk-overbrowsing has received--quite justifiably--much attention, by range and wildlife researchers. Range investigators found that heavy utilization and, especially, overbrowsing of quaking aspen is compounded by (and conclusions confounded with) invasion of aspen groves by conifers. One thorough study of this dual threat to "quakies" in the Southern Rocky Mountains was conducted in Rocky Mountain National Park and Roosevelt and Arapahoe National Forests, two large neighboring parcels of public elk range (Kaye et al., 2005). In addition to its original research (which demonstrated what any observant and impartial observer already knew), this paper by Kaye et al. (2005) provided a thorough bibliography of this on-going threat to and, on all-too many ranges, loss of natural vegetation and wildlife habitat.

Shown immediately below were several conspicuous understorey species in quaking aspen groves. Some of these were growing on mesic sites such as along streams where Douglas-fir was also found while others were on drier upslopes as in big sagebrush steppe. Relative soil moisture content was noted for the specific species.

286. Heartleaf arnica (Arnica cordifolia)- This low-growing composite is one of the more common forbs in the understorey of quaking aspen groves and woodlands in the Southern Rocky Mountains. These specimens grew on a relatively moist lowland site within 50 yards or so of a stream. Their neighbor was the next forb shown. Roosevelt National Forest, Jackson County, Colorado. June.

287. Colorado or blue columbine (Aquilegia caerulea)- The State Flower of the Centennial State is one of the forbs growing most consistently in quaking aspen groves though not usually in large numbers (but like women it does not take many when you're this good-a-lookin'). Beginning students should take note of the leaf shape of this member of the Ranunculaceae (the buttercup or crowfoot family). This same general pattern of palmately compound leaves, usually with a partly enclosing sheath-like basal leaf, is a consistent characteristic of this family. Roosevelt National Forest, Jackson County, Colorado. June.

288. Shoot apex and detail of inflorescence of blue or Colorado columbine- Students should also pay attention to the basic structure and arrangement of parts of the inflorescence of the columbine. There are numerous range and forest forbs that are members of the buttercup family including larkspur (Delphinium spp), marsh marigold (Caltha spp.), wind flower (Anemone spp.), and Clematis spp. Some of these genera are especially common in the Rocky Mountains, both in various forest zones and the alpine. Other of these genera commonly occur on grasslands including the eastern prairies and the deciduous forests like the oak-hickory type. Roosevelt National Forest, Jackson County, Colorado. June.

289. Rocky Mountain locoweed, white loco, or silky crazyweed (or other combinations of these descriptive words)- Oxytropis sericea is another showy forb found in aspen groves and, in particular, along edges of groves. This robust example was growing where an aspen grove adjoined a subalpine mountain meadow. The pigmented spot on the keel of this papilinaceous legume allowed positive identification to this rather varied species.

Oxytropis is one of the more intriguing genera of poisonous range plants, and O. sericea has figured prominently in the saga. Some Oxytropis species and some of the Astragalus species are classic locoweeds, those that induce locoism or loco poisoning. This condition has been the subject of scientific study for over a century. The poisonous principle was identified as a group of indolizidine alkaloids. Summary coverage was provided by Cheeke and Shull (1985, ps.142-146). Recently O. sericea has been implicated in big brisket, high mountain disease, or congestive right hear failure. For detailed recent treatment see Burrows and Tyrl (2001, ps. 594-599). And never forget Kingsbury (1964, ps. 306-311). Investigations with Oxytropis, including O. sericea, have been reported consistently in the peer-reviewed proceedings of the International Symposium on Poisonous Plants. Readers with a joint enjoyment of Chemistry, Botany, and Range Management can get a full-course feast there. The subject of poisonous range plants has long fascinated those who study and report on "things range". The current writer was no exception.

Rocky Mountain National Park, Larimer County, Colorado. June.

290. Inflorescence of elephant head or little red elephant (Pedicularis groenlandica= Elephantella groenlandica)- This is another showy member of the aspen community (and adjoining forest cover types such as interior Douglas fir). Elephant head was described in both Notes on Western Range Forbs (Hermann, 1966, ps. 264-266) and Range Plant Handbook (Forest Service, 1941, p. W143) where it was described as usually no higher than Fair forage for small ruminants. It is very distinctive and adds species diversity to range plant communities. Elephant head is an easy one to learn (and to impress others with one's knowledge of native plants). This one grew along the edge of an aspen grove in association with cowparsnip (Heracleum lanatum).

Rocky Mountain National Park, Grand County, Colorado. Early August.

291. Cow parsnip (Heracleum lanatum)- This rank-growing rascal is common along mountain streams throughout the Rockies. Where aspen groves are associated with springs, seeps, streams, etc. cow parsnip is a large conspicuous forb of the aspen cover type. Rocky Mountain National Park, Grand County, Colorado. July.

292. Inflorescence of cow parsnip- Cow parsnip is one of many members of the Umbelliferae (=Apiaceae). This traditional name of this family comes from the distinguishing feature of the umbel type inflorescence. An umbel is a more-or-less flat-topped or umberella-shaped indeterminate inflorescence having all the flowers borne on pedicels of approximately equal length and arising from a common point. This arrangement results in the characteristic "umberella" of flowers as seen here. Rocky Mountain National Park, Grand County, Colorado. July.

293. Fruit of cow parsnip- This portion or section of a cow parsnip inflorescence was bearing fruit. This fruit type is a schizocarp, a dry indehiscent fruit from a syncarpous (having two or more fused carpels, the ovule-bearing structures of the flower) gynoecium, in which the carpels separate from each other into one-seeded segments. Montplier Canyon, Caribou National Forest. Cache County, Utah. July.

294. False helleborne or cornhusk lily (Veratrum tenuipetalum)- According to some of the more recent treatments (eg. Weber and Wittmann, 2001) this is the only species of Veratrum found in the Southern Rocky Mountains in Colorado, but previous work (eg. Dayton, 1960) reported that western false hellebore (V. californicum) occurred in Colorado and, in fact, in all of the 11 Western States. From the current author's observation V. californicum has broadly ovate leaves that are clearly distinct from the lanceolate leaves of the individuals shown here which were therefore designated as V. tenuipetalum. More importantly from this authors perspective was presence of the numerous conspicuous lanceolate leaves on the flower stalk of these plants in contrast to the leafless rachis of the ovate-leaved plants displayed immediately below.

The plants presented in this slide were representative of many growing prolificly at the edge of a the last grove of quaking aspen shown above (Grand County, Colorado). The toxicological property of Veratrum species and the resultant phenomenon of the cyclops lamb was noted in the first caption of this quaking aspen series. The most recent comprehensive reference tretment was that of Burrows and Tyrl (2001, ps. 782-787). These authors did not list V. tenuipetalum but discussed all Veratrum species as toxic. They too showed V. californicum as native to Colorado, western Colorado.

Grand County, Colorado, Colorado. June.

295. Western false helleborne or corn lily (V. californicum)- The broadly ovate leaves of these plants appeared to to this author to be distinctly different from those examples shown immediately above. Even more definitive was the presence of the lanceolate leaves all along the flowering stalk of the plants your author labeled V. tenuipetalum immediately above and the leafless rachis of the plants shown here and labeled V. californicum. Yes, indeed these species-- as interpreted by your author-- both grew in northern Colorado and in adjoining large counties, but the two were on opposite sides of the Continental Divide. The species shown here was on the West Slope and the one shown above on the East Slope. Numerous plant species have been distinguished and separated out on the basis of morphological features much less distinctive and obvious that these, and with less geographic separation than that of the Great Divide. In the first comprehensive maunal of Colorado plant life, the classic Flora of Colorado, Rydberg (1906, p. 76) showed both of these species (V. speciosum was used as the synonym for V. Californicum). Rydberg separated them on oval versus oblong-lanceolate petals. This might be a good research project for some budding plant taxonomist.

One last lesson from this example, the author bought a copy of Rydberg's Flora of Colorado that had been discarded from, first, the University of Montana and, next, Montana State University (discarded stamps from both institutions). Do these two universities, both of which have programs in Forestry and Range Management, have another copy? Just because a book is a century old does not mean it is no longer valid or of use. The currently commonplace practice of discarding texts and references by university libraries based on nothing but copyright dates and how many times the book was checked out is as stupid and short-sighted as it is sinful to knowledge. Oh yes, of course there is inter-library loan. This author can tell you about that too.

The specimens presented here grew inside of and all around the quaking aspen grove shown in the first two slides of this series (Routt National Forest, Jackson County, Colorado, July).

296. A savanna of High Plains grassland of blue grama, black grama, buffalograss, silver bluestem, galleta, wolftail (Lycurus phleoides), and threeawns with scattered one-seed juniper (Juniperus monosperma). Under disturbance this savanna community is often transitory to juniper-pinyon pine (Pinus edulis) woodland which may in turn increase in tree density to form a closed canopy forest over the climax mixed prairie or shortgrass plains. This latter state is afforestation, an anthropogenic woody invasion. It is one of the worst forms of range deterioration (retrogression) in North America. This massive-scale retrogression is due to numerous factors like overgrazing, fire suppression, transportation systems, and adjoining commercial and residential development. Changing climate and succession to another climax is possible, but likely does not explain the huge increases in juniper-pinyon woodland across the American West.

Note: Changes in vegetation due to cycles of changing climate was a popular concept among pioneer plant ecologists (eg. sunspot activity was a “pet” theory) a century before some contemporary climatologists and ecologists starting grandstanding and crowing about human-induced “global warming” and possible consequent modifications of vegetation.

Guadalupe County, New Mexico. July. SRM 707 (Blue Grama-Sideoats Grama-Black Grama) X SRM 504 (Juniper-Pinyon Pine Woodlands) combination. No single FRES or Kuchler designation describes this cover type which probably covered more land than the Juniper-Pinyon Woodland Ecosystem (FRES No. 35), K-21 (Juniper-Pinyon Pine Woodland) presented immediately below. The vegetation seen here, which again is probably representative of most of the pre-Columbian plant communities that included these conifers as associates, would be best categorized as FRES No. 38 (Plains Grasslands Ecosystem), Kuchler-58 (Gramagrass-Buffalograss), with overstory elements of FRES No. 35 (Pinyon-Juniper Woodland Ecosystem), K-21 (Juniper-Pinyon Pine Woodland). Southwestern Tablelands- Central New Mexico Plains Ecoregion, 26o (Omernik and Griffith, 2006).

297. Pinyon pine- juniper woodland- The highest reaches of the Upper Sonoran life zone or perhaps the Transition life zone in the Capitan Mountains of southern New Mexico support this textbook example of the pinyon pine-juniper woodland. This stand on a northeast slope is probably the climax vegetation and not the woody invasion of a deteriorated mountain grassland range. In addition to pinyon pine and one-seed juniper, alligator juniper (Juniperus deppeana), Gambel oak, and an occasional ponderosa pine "round out" a woodland community with a sparse understory of short- and mid-grasses. Lincoln County, New Mexico. June. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Pine Woodland). SRM 504 (Juniper-Pinyon Pine Woodlands); SAF 239 (Pinyon-Juniper). Pinyon-Juniper Series in Great Basin Conifer Woodland biotic community of Brown et al. (1998). Arizona/New Mexico Mountains- Madrean Lower Montane Woodlands Ecoeregion,, 23b (Omernik and Griffith, 2003).

298. Interior and soil profile of a pinyon pine-juniper woodland community here dominated by the pinyon pine as a consociation- A few one-seeded junipers are scattered throughout. Lincoln County, New Mexico. June. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Pine Woodland). SRM 504 (Juniper-Pinyon Pine Woodlands); SAF 239 (Pinyon-Juniper). Pinyon-Juniper Series in Great Basin Conifer Woodland biotic community of Brown et al. (1998). Arizona/New Mexico Mountains- Madrean Lower Montane Woodlands Ecoeregion,, 23b (Omernik and Griffith, 2003).

299. The classic pinyon-juniper zone of the Intermountain West-In addition to the pinyon pine, Utah juniper (Juniperus osteosperma) is the co-dominant conifer.Rocky Mountain juniper (J. scopulorum) is a minor but well- represented member of this community.The conspicuous light-green deciduous trees are Rocky Mountain maple (Acer glabrum). Grasslands and/or shrublands often occur interspersed among P-J woodlands as seen here. The rimrock land form is a picturesque feature of Basin and Range and Rocky Mountain physiographic provinces as here in the Wasatch Range. Transition life zone of C. Hart Merriam.Cache National Forest, Cache County, Utah. July. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Pine Woodland). SRM 412 (Juniper-Pinyon Woodland); SAF 239 (Pinyon-Juniper). Pinyon-Juniper Series in Great Basin Conifer Woodland biotic community of Brown et al. (1998). Wasatch and Unita Mountains- Semiarid Foothills Ecoregion, 19f (Woods et al., 2001).

300. Interior of P-J woodland seen in the previous scene— Understory grasses include blue grama, Indian ricegrass, western wheatgrass, galleta, and muhleys (Muhlenbergia spp.). Cache National Forest. Cache County, Utah. July. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper- Pinyon Pine Woodland). SRM 412 (Juniper-Pinyon Woodland); SAF 239 (Pinyon-Juniper). Pinyon-Juniper Series in Great Basin Conifer Woodland biotic community of Brown et al. (1998). Wasatch and Unita Mountains- Semiarid Foothills Ecoregion, 19f (Woods et al., 2001).

301. Edge of the P-J woodland and adjoining grassland seen in two preceding shots- Rocky Mountain maple is conspicuous. In addition to forbs, herbs include the dominant grasses blue grama, bluebunch and western wheatgrassses, and galleta.

Cache National Forest, Cache County, Utah. July. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Pine Woodland). SRM 412 (Juniper-Pinyon Woodland); SAF 239 (Pinyon-Juniper). Pinyon-Juniper Series in Great Basin Conifer Woodland biotic community of Brown et al. (1998). Wasatch and Unita Mountains-Semiarid Foothills Ecoregion, 19f (Woods et al., 2001).

302. The co-dominants of the Intermountain P-J woodland type: pinyon pine (left) and Utah juniper (right). Big sagebrush dominates the understory but western wheatgrass and blue grama also are well-represented. The three main layers of this range type are obvious. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper- Pinyon Pine Woodland). SRM 412 (Juniper-Pinyon Woodland); SAF 239 (Pinyon-Juniper). Pinyon-Juniper Series in Great Basin Conifer Woodland biotic community of Brown et al. (1998).

303. Petered up- Highest elevational limit of pinyon pine-juniper woodland in the Sagre de Cristo range just above the San Luis Valley. Above this foothill elevation (approximately 7200-7300 feet) and on a xeric west slope was the beginning of a rather scant Douglas-fir forest in the Lower Montane zone. Some smaller Douglas-fir trees were growing on the upper slopes and crest of hills seen here. Most of the low-growing shrub were was current. There were also some plants of mountain ninebrk (Physocarpus monogynus) and willow of undetermined species (Salix sp.) lower down by a small stream.

Herbaceous species were lacking suggesting that this hillside range had been overgrazed and severly depleted.

Saguache County, Colorado. Late June.

One of the most biologically diverse (and beautiful) forms of the pinyon pine-juniper woodland is the oak-pinyon pine-juniper woodland. There is great species diversity in the tree, shrub, and herbaceous layers of this southwestern North American range woodland. One of the best geographic locations for this range vegetation is in the Big Bend area of west Texas and northern Chihuhua where floristic elements from the Rio Grande Plains, Edwards Plateau, Southern Great Plains, and Chihuhuan and Trans-Pecos Basin and Range "blend" to produce an amazingly varied and colorful array of range plants in turn responsible for a remarkable development of this range cover type. The mixed oak-Mexican pinyon pine-juniper woodland begins in mountain foothills above basins and bajadas of Chihuhuan Desert and lower foothills of various zonal grassland communities.

There are various range cover types of Chihuhuan Desert and semidesert (Chihuhuan) grasslands below (ie. "down the mountain and out on the flats") the oak-Mexican pinyon pine-juniper montane woodland. These lower, more xeric range types were covered in this publication under Chihuhuan Desert (Shrublands) and semidesert grasslands (Grasslands).

Arguably one of the most accessable examples of the oak-pinyon pine-juniper woodland range type is in the Chisos Mountains. The following set of photographs was taken from Green Gulch in the Chisos Range. Enjoy the scenery.

The first two photographs in this set were landscape-scale views that displayed the physiography of the Chisos Mountains and the physiogonomy, structure, and general composition of their range vegetation.

304. Oak-pinyon pine-juniper montane woodland in the Basin and Range- Deep in the core of the Chisos Mountains a tremendously varied montane range plant community had developed consisting of several layers of vegetation: 1) tree, 2) shrubs that typically formed two layers, and 3) herbaceous plants consisting of tall-, mid-, and shortgrass species as well as forbs. Even the tree layer of this woodland range was more complex than might be expected due to presence of mistletoe as a parasitic epiphyte.

Coniferous tree species included Mexican pinyon pine (Pinus cembroides), the ultimate climax conifer, alligator juniper (Juniperus deppeana), redberry or Pinchot juniper (J. pinchotii), rose-fruit juniper (J. erythrocarpa), and, less commonly, weeping or drooping juniper (J. flaccida). Woody angiosperm species which included some individuals of tree shape and size were mostly Emory oak (Quercus emoryi) and gray oak (Q. grisea). These were common trees within the photographic view shown here. Other oaks in the Chisos that attain tree deminsions and shape yet which were not observed within field of this photograph included Chisos red or Graves oak (Q. gravesii= Q. chesosensis), chinkapin oak (Q. muehlenbergii), and netleaf oak (Q. rugosa). Uncommon to rare species of oaks that have tree form in the Chisos ncluded Chisos oak (Q. graciliformis) and lateleaf oak (Q. tardifolia). Common scrub oak species scattered throughout the range vegetation presented here included gray oak and netleaf oak (two of several oak species having individual plants that grow in either tree or shrub form) and Vasey shin oak (Q. vaseyana= Qpungens var. vaseyana= Q. undulata var. vaseyana). An uncommon but extremely conspicuous tree species was Texas madrone or naked Indian or lady's leg (Arbutus texana) of the Ericaceae, heath or heather family.

Other angiosperm species on this woodland range that usually have shrub shape and size but sometimes attain tree form or size present included three sumac species: lanceleaf sumac (Rhus lanceolata= R. copallina var. lanceolata), evergreen or tobacco sumac (Rhus virens subsp. virens), and littleleaf sumac (Rhus microphylla). One of the most common angiosperm shrubs was golden or yellow currant (Ribes aureum). The most conspicuous shrubs in many spots were the succulent or succulent-like species including various pricklypear cactii (mostly Opuntia englemannii), smooth sotol (Dasylirion leiphyllum), and lechuguilla (Agave lechuguilla).

Grasses were all native perennial species with Eurasian cool-season annuals like cheatgrass (Bromus tectorum) present at trace amounts. Little bluestem (Andropogon scoparius= Schizachyrium scoparium) and cane bluesteem (A. barbinodis= Bothriochloa barbinodis) were grass species of largest mature size. Little bluestem was interpreted as a tallgrass species. Sideoats grama (Bouteloua curtipendula) was the dominant mid-grass species. Chino grama or chinograss (B. ramosa) was the most abundant grass, but cumulative foliar cover of this species was locally less than that of larger-growing species including cane bluestem and sideoats grama. Chino grama was viewed as a shortgrass species of which grass group it was dominant. Other Bouteloua species included blue grama (B. gracilis), hairy grama (B. hirsuta), and, very infrequently, red grama (B. trifida). Threeawn species were also common (and always the taxonomic nightmare) with red threeawn (Aristida longistea= A. purpurea var. longiseta) the major member of this taxon. Mountain muhly (Muhlenbergia montana) was found rarely (and always in battered condition). Overall there was no dominant grass species.

Forbs were inconsequential at the early summer season shown in these photographs.

Green Gulch, Big Bend National Park, Brewster County, Texas. June. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak varaint of SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series, 123.32, of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24d (Griffith et al., 2004).

305. Climax vegetation of an oak-pinyon pine-juniper woodland- Foothills of Chisos Mountains and an almost unbelieveable array of range plants in another panaramic view of Chihuhuan or Madrean montane woodland.. The two tallest trees in midground were Mexican pinyon pine. This species has usually been interpreted as the potential natural dominant gymnosperm of this range cover type. Associate coniferous species are the various Juniperus species listed above. The two junipers in the foreground of this slide were redberry or Pinchot juniper. Shrub in right foreground (right corner of photograph) was gray oak. Smooth sotol was also present. Grasses included sideoats and chino grama and cane bluestem.

Green Gulch, Big Bend National Park, Brewster County, Texas. June, early estival aspect (prior to onset of main summer rains and most grass "green-up"). FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak variant of SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series, 123.32, of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al, 1998). Chihuhuan Deserts- Chihuhuan Montane Woodland Ecoregion 24d (Griffith et al., 2004).

306. Inside Chisos Mountain montane woodland range- Details of oak-pinyon pine-juniper woodland vegetation inside a mountain range in the Trans-Pecos Basin and Range. In this "photo-plot" there was a stand of Mexican pinyon pine with a predominantly shrub understorey sotol, pricklypear, gray oak, and golden currant. There were some Pinchot or red berry junipers (eg. needles of one in right foreground). Chino and sideoats gramas were main grasses.

Green Gulch, Big Bend National Park. June, early estival aspect. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak variant of SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series, 123.32, of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodland Ecoregion 24d (Griffith et al., 2004).

307. Chisos Mountains montane range- A detailed view inside the oak-Mexican pinyon pine-juniper montane woodland. Taller conifers (eg. three in midground) were Mexican pinyon pine. Shrub in right foreground was a much-brancned redberry or Pincot junipe. According to Powell (1988ps. 38-41) redberry and rose-fruit juniper integrade to the extent that there may be a J. pinchotti X J. erythrocarpa hybrid in the Chisos Mountain Basin. Sotol, including a prominently blooming specimen, was a dominant shrub in mid foreground. Pricklypear was another prominent shrub. Major grasses visible were little and cane bluestems.

Green Gulch, Big Bend National Park, June, early estival aspect. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak variant of SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series, 123.32, of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24d (Griffith et al., 2004).

308. Chisos Mountains montane woodland range at its pinnacle- Textbook view of vegetation of mixed oak-Mexican pinyon pine-mixed juniper woodland. Three coniferous trees in center (large mature one flanked by two small ones) was Mexican pinyon pine. These in turn flanked by either redberry juniper or rose-fruit juniper (these two species are very difficult to tell apart). Grass species in foreground were cane and little bluestem, sideoats grama, and red threeawn. Sotol also visible, including flower stalk of one in left foreground.

309. Cool sweep of Chisos Mountains vegetation- First-timers to these hills find it "hard to imagine" that the Chihuan Desert lies less than 2000 feet below these densely wooded Chisos Mountains (and with an array of distinctive zones of grassland vegetation in between), and that such differences in range vegetation are largely a function of elevation and other abiotic factors associated with elevational gradations.

Range vegetation shown here was a mixed oak-Mexican pinyon pine-juniper woodland. This was a climax plant community with a prominent physiogonomy, rich species composition, and complex structure. Major grass species in this "photo-transect" included cane bluestem, little bluestem, sideoats grama, chino grama, and red threeawn. The conspicuous shrubs in foreground were gray oak of characteristic coloration. Larger trees that were visible in the far foreground were Mexican pinyon pine, alligator juniper, Emory oak, and Texas madrone.

Green Gulch, Big Bend National Park, June, early estival aspect. FRES No. 35 ((Pinyon-Juniper Ecosystem). K-21 ((Juniper-Pinyon Woodland). Oak variant of SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series, 123.32, of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24d (Griffith et al., 2004).

310. Montane browse above the Chihuhuan Desert- Another landscape-scale photograph of the Chisos Mountains with mixed oak-Mexican pinyon pine-juniper montane woodland. This panoramic view featured details of the browse layer of this range cover type. Shrub species in the foreground included (roughly left to right allowing for intermixing of branches) golden currant, smooth sotol, littleleaf sumac, evergreen sumac, gray oak, and Emory oak. The large tree was Emory oak. Primarily redberry or Pinchot juniper, rose-fruit juniper, and gray oak in basin of background.

Big Bend National Park, Brewster County, Texas. June, early estival aspect. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak variant of SRM 504 (Juniper-Pinyon Pine Wooodland). SAF 239 (Pinyon - Juniper).Oak-Pine Series, 123.32, of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24d (Griffith et al., 2004).

311. Rangeman's picture postcard of Chisos Mountain range- At the base of a mountain slope topped with Casa Grande was an all-in-one shot of the oak-Mexican pinyon pine-juniper woodland range type followed by a second slide showing overall species compostion and structure of this montane vegetation. Tallest tree at far left of both photographs was Mexican pinyon pine. Immediately to the right of the pine was an Emory oak with gary oak to its right. Alligator juniper, redberry juniper, rose-fruit juniper, and Texas madrone were the other major trees higher up on the mountain side. In the foreground the understorey was mostly herbaceous with red threeawn the dominant species. Mule deer (Odocoileus hemionus) were nosing around in this rank-growing grass, perhaps looking for acorns or pine 'nuts".

Big Bend National Park, Brewster County, Texas. June, early estival aspect. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak variant SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series 123.32 of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24d (Griffith et al., 2004).

Autumn in the Chisos Mountains- the following sequence of slides portrayed pinyon pine-juniper woodland range in the Chisos Mountains during early fall, the autumnal aspcect of this range vegetation. In addition to subtle differences in natural color of the vegetation (foliar tones) the differences between color in slides of the estival aspect (above) versus autumnal aspect (below) some of the difference in color were due to differences between Kodachrome 64 (estival slides) and Provia 100F (autumnal aspect) and Hewledt Packard and Epson Perfection scanners, respectively. The superiority of Kodachrome was obvious, as was the cobalt-blue, azure sky of the Trans-Pecos Region ("God's Country").

312. Range splendor in the Chisos Mountains, a Chisos composite- Overall or composite view at landscape scale of the mixed oak-pinyon pine-juniper-grass woodland in the Chisos Mountains of Trans-Pecos Basin and Range in the Big Bend Country of Texas and Chihuhua, Mexico. Major tree or large shrub species were Mexican pinyon pine, redberry juniper, rose-fruit juniper, alligator juniper, drooping juniper, gry oak (usually more of a shrub), Emory oak, and Texas madrone. The most abundant shrubs were smooth sotol, various pricklypear species, gray oak, littleleaf sumac (Rhus microphylla), mountain-mahogany (Cercocarpus breviflorus, C. betuloides), and golden currant. Major herbaceous species were grasses including cane bluestem, little bluestem, sideoats grama, chino grama, bullgrass (Muhlenbergia emersleyi), and red and/or, Wright's threeawn, and Arizona threeawn.

Bigger tree in left foreground was Mexican pinyon pine.

Big Bend National Park, Brewster County, Texas. Early October, early autumnal aspect. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak variant SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series 123.32 of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24d (Griffith et al., 2004).

313. An amazing array of plant life in the Chisos Range- The succulent shrub, smooth sotol (Dasylirion leiophyllum), was the feature of this landscapes-cale image in the rugged Chisos Mountains of the Trans-Pecos Basin and Range province. Other important shrubs included mountain-mahogany and golden current. Gray and Emory oaks grew as medium-sized shrubs up to respectable tree-size. In the background rose-fruit, alligator,and drrooping or weeping junipers (cedars) and Mexican pinyon-pine were aboreal dominants. The most common grasses in this pannning "photo-transect" were little bluestem and sideoats grama with considerable cover of Wright's threeawn, Havard's threeawn, and Arizona threeawn.

314. Splendor in the array of Chisos Mountains plant life- Mexican pinyon pine, the climax dominant pine (left), and redberry juniper and alligator juniper (side-by-side; right) with an array of understorey grassse, including little bluestem, cane bluestem, sideoats grama, chino grama, Wright's threeawn, Havard's threeawn, and Arizona threeawns. There were several plants of lechuguilla (Agave lechuguilla) that produced considerable cover in this understorey. Lechuguilla was part of a lower shrub layer (that is, until sexual/flowering shoots shot up to heights sometimes exceeding ten feet). Purplefruited pricklypear (Opuntia phaeacantha) was widespread and also part of the lower shrub layer.

315. King of the Chisos Mountain vegetation- Two nice specimens of Mexican pinyon pine with a lower shrub layer including the conspicuous purplefruited pricklypear prominent along with lower-growing plants of Emory oak. Although not visible in these two tree-featured images, there was a well-developed haerbaceous layer made up of such grasses as little bluestem, cane bluestem, sideoats grama, chino grama, bullgrass muhly, Havard's threeawn, and Arizona threeawn. There were some widely scatttered plants of birchleaf mountain-mahogany (Cercocarpos betuloides).

316. Chisos Mountain feedstuffs- Representative species of middle and lower shrub layers and the herbaceous layer of a Mexican pinyon pine-juniper-mixed oak-grass woodland in the Chisos Mountains. Tallest plants in both of these slides was birchleaf mountain-mahogany. In the upper or first slide there were two shrubs of the agave family (Agavaceae) or, perhaps more correctly, of the agave subfamily (Agavoideae) of the lily family (Liliaceae ): smooth sotol (Dasylirion leiophyllum) and foothill beargrass (Nolina erupens). Smooth sotol (young plant at non-blooming stage) was also in the range vegetation presented in the the lower or second slide (although it was not distinct in the slide following scanning by an Epson Perfection scanner). Grass species present in both slides included bullgrass or bullgrass muhly, sideoats grama, and comparatively small plants of little bluestem.

317. Raw beauty of the Chisos Range- The ragged "teeth" of the bare tops of the Chisos Mountains in the Big Bend Country. Below these mostly marine limestone "cusps" are woodlands of Mexican pinyon pine and several species of "cedar" or junipers including redberry, alligator, rosefruit, and drooping juniper. There are also some trees of Texas madrone (Arbutus texana= A. xalapensis) along with the shrubs, including numerous succulents, and herbaceous species shown herein. The crown of the tree in foreground of the second slide was that of a Mexico pinyon pine.

318. Dazzling diversity in the Chisos Range- Early evening sunlight made for a nice color tone to this southwest slope just below the bare rock of a peak in the Chisos Mountains of the Texas Big Bend Country. Tree species present included Mexican pinyon pine, rosefruit juniper, redberry juniper, alligator juniper, drooping or weeping juniper,Texas madrone, gray oak, Emory oak, and Grave's or Chisos red oak (Quercus gravesii= Q. texana). Lechuguilla was conspicuous in center foreground. Grasses included cane bluestem, sideoats grama, and several Aristida species of this "tangled taxonomic mess" including Havard's threeawn, Wright's threeawn, and spider threeawn (Aristida ternipes= A. ternipes var. ternipes).

319. Stately understorey of Chisos Mountain woodland- Three robust plants of Havard's threeawn with sideoats grama, State Grass of Texas, at edge of a woodland made up of alligator juniper drooping or weeping juniper, Mexican pinyon pine, and gray oak in the Chisos Mountains of the Trans-Pecos section of the Basin and Range physiographic province. More specifically--though it encompasses a vast area of wild "real estate"--this rangeman's "dream-come-true" is in the Big Bend Country of Texas and the Mexican states of Chihuahua and Coahuila.

Big Bend National Park, Brewster County, Texas. Early October, grain-ripe stage of both eragrostoid species.

320. Woody and herbaceous in Chisos Mountain range- Pendant leaders (branches) of drooping juniper and purplefruit pricklypear provided a backdrop for sexual shoots of sideoats growing in the understorey of a Mexican pinyon pine-mixed juniper woodland in the Chisos Mountains in the Big Bend Country of Trans-Pecos Texas.

Big Bend National Park, Brewster County, Texas. Early October, grain-ripe stage of the State Grass of Texas.

321. Two of the woodland understorey- Havard's threeawn in front of sideoats grama in the understorey of a species-rich Mexican pinyon pine-mixed juniper-mixed oak woodland in the Chisos Mountains located in the Trans-Pecos section of the vast Basin and Range physiographic province. Within this botanically diverse range cover type that develops in the Chisos Range there are, along with Havard's threeawn, numerous other threeawn (Aristida) species including A. wrightii, A. longiseta, A. arizonica, and A. ternipes. Aristida species in general, and especially those in what some agrologists regard as the A. purpurea complex, are a taxonomic and field identification "nightmare-come- true. A. havardii is one threeawn species that is readily distinguishable on this pinyon-juniper woodland and adjoining desert plains (semidesert) grassland and Chihuhuan Desert ranges of the Big Bend Paradise.

Big Bend National Park, Brewster County, Texas. Early October, grain-ripe stage of these eragrostoid grasses.

322. Now time for a neighboring shrub- One plant of rubber rabbitbrush (Chrysothamnus viscidiflorus= C. spathulatus) was presented in the first slide that was a member of the lower shrub layer and the intermingled herbaceous layer of a Mexican pinyon pine-juniper-mixed oak-grass woodland in the Chisos Mountains. This plant was associated with birchleaf mountain-mahogany, smooth sotol, and foothill beargrass in the same layer of range vegetation along with such herbaceous species as bullgrass or bullgrass muhly, sideoats grama, chino grama, Wright's threeawn, spider threeawn, and little bluestem. There were relatively few compositious forbs in this range plant community. Instead, composites were represented by this woody member of the Astereae (aster tribe).

The second slide presented the tiny and brilliant yellow flowers of this same plant. Rubber rabbitbrush is one of the most widely distributed composite shrubs of North America. its species range extends sporadically across the Seventeen Western Range States and the three westernmost Canadian provinces.

Rubber rabbitbrush is one of the most abundant, most widely distributed of the North American Chrysothamnus species. It is an extremely important shrub species across much of the Western Range Region. Rubber rabbitbrush was even included in the restrictive shrub compendium assembled by Francis (2004, 203-205). There is a Natural Resources Conservation Service plant fact sheet devoted to rabbit rabbitbrush (Scheinost et al., 2010). Obviously such standards as Range Plant Handbook (Forest Service, 1940, p. B56) included rabbit rabbitbrush. Recent treatments of Chrysothamnus have moved numerous, former Chrysothamnus species to three genera! This conversion was shown in very useful fashion by Allred and Ivey (2012, specifically ps. 118-119 for C. nauseosus). These authors gave a key for the nine (9) taxonomic varieties found in New Mexico and added the appropriate warning "Good luck!" (Allred and ivey, 2012. p. 119). The local authority on rubber rabbitbrush remained Powell (1988, ps. 440-441) whose key showed the specimen presented here to be a plant of Guadalupe rabbitbrush (C. nauseosus subsp. texensis).

Big Bend National Park, Brewster County, Texas. Early October, peak-bloom (and no doubt about that) phenological stage

Scheinost, P.L., J. Scianna, D.G. Ogle. 2010. Plant fact sheet for rubber rabbitbrush (Ericameria nauseosa). USDA-Natural Resources Conservation Service, Pullman Plant Materials Center, Pullman, WA.

323. The dry side and after a fire- "Just around the corner" from the location of the two immediately preceding slides the range vegetation took on this drastic difference in physiogonomy and species composition. Obviously a fire had modified this vegetation in the not-too-distant past. While the fire "opened up" this range plant community it was probably the xeric, predominately west slope that was responsible for a grass-scrub savanna variant form of the oak-Mexican pinyon pine-juniper woodland type.

The centerpiece showy succulent was Havard agave (Agave havardiana) which was, as if on cue, at full-bloom, and already starting to die as it was fulfilling its once-in-a-lifetime role to reproduce sexually therby giving its species another opportunity for natural selection. Red-fruited shrub in right foreground was littleleaf sumac. Top-killed and resprouting tree at far left foreground was Emory oak. Shrub to left front of agave was redberry juniper which had also been top-killed and subsequently resprouted. Redberry or Pinchot juniper is one of the very few Juniperus species to resprout, a rare characteristic of conifers. The largest tree (directly behind agave) on the slope was a drooping or weeping juniper. This plant was not bearing cones, but even from a distance the descending, dead, outer branches (undoubedly fire-killed) gave this species away as far as it could be seen. This Juniperus species does not resprout, but this particular tree had attained size enough to withstand-- minus portions of some outer branches-- the heat of what was likely an upslope, hot, heading fire.

Predominate grasses were little bluestem, cane bluestem, and sideoats grama.

Casa Grande crowned the spectacle.

Chisos Basin, Big Bend National Park. June. FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper -Pinyon Woodland). Oak variant of SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak -Pine Series, 123.32, of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24d (Griffith et al., 2004)..

324. Chisos Basin range- Range vegetation in Chisos Basin. The rich flora of climax oak-Mexican pinyon pine-juniper woodland was on display in this view across the Chisos Basin of the Chisos Mountains. Center conifer was Mexican pinyon, the climax dominant gymnosperm. Two Havard agaves in full-bloom "accompanied" the pine. The shrub in center foreground was of the Emory oak scrub form. Grasses included sideoats grama, cane bluestem, red threeawn, and chino grama.

Chisos Basin, Big Bend National Park, Brewster County, Texas June, early estival aspect. ,FRES No. 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak variant of SRN 504 (Juniper- Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series, 123.32, of Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24d (Griffith et al., 2004).

325. Range vegetation of Chisos Basin- Detail of range plants in Chisos Basin. A mixture of herbaceous and woody range plants were easily identified in this photograph. Englemann pricklypear and smooth sotol were in left and right foreground. Sideoats grama, a decreaser and the climax dominant on this location, was in center foreground. Other major grass species included cane bluestem, chino grama, and red threeawn. Shrubs of gray oak were in center midground. Foremost conifer (rounded crownin right midground was redberry or Pinchot juniper. Conifer behind and to left of juniper was a young Mexican pinyon pine. and shrubs.

There were not many forbs growing at the early summer season at time of this photograph. As to be expected most forbs were composites. Most of the dead shoots of forbs were cool-season annuals of the Umbelliferaeh

Chisos Basin, Big Bend Natioal Park, Brewswter County, Tesas. June, early estival aspect. FRES No., 35 (Pinyon-Juniper Ecosystem). K-21 (Juniper-Pinyon Woodland). Oak variant of SRM 504 (Juniper-Pinyon Pine Woodland). SAF 239 (Pinyon - Juniper). Oak-Pine Series123.32, oif Madrean Evergreen Forest and Woodland, 123.3 (Brown et al., 1998). Chihuhuan Deserts- Chihuhuan Montane Woodlands Ecoregion 24 d (Griffith et al., 2004).

326. Smooth sotol or desert candle (Dasylirion leiophyllum)- Full-bloom stage in smooth sotol on a range of the oak-Mexican pinyon pine-juniper woodland type. Green Gulch,.Big Bend National Park, Brewster county, Teaas, June.

327. Inflorescence of smooth sotol or desert candle- Bureau of Land Magement Valley of Fire Recreational Area, Lincoln County, New Mexico. June.

328. Immature fruit of smooth sotol- A flowering-fruiting stalk of smooth sotol with an abundance of immature fruit. The Dasylirion species are dioecious so this was a pregnant girl plant. According to Powell (1988, p. 70) smooth sotol is the most common Dasylirion species in the Trans-Pecos Basin and Range area.

Presidio County, Texas. June.

329. Lechuguilla (Agave lechuguilla)- This is probably the most abundant Agave species in the Trans-Pecos Basin and Range area. In fact, lechuguilla "has one of the most extensive ranges of the agaves" (Gentry, 1982, p. 154). Lechuguilla is also one of the most easily identified (usually recognized immediately) by the high number of rosettes growing in clusters or groups. A. lechuguilla is a highly modular organism. Each of the basal rosettes is a module (a clone= ramet) of a genetic indivisual (genet). Most reproduction is asexual via suckering from rhizomes or rhizome-like structures (ie. "rootstocks"). Gentry (1982, p. 154) stated that numbers of rosettes "probably exceed those of all other native agaves". Gentry (1982, ps. 30-31) described the Agave rosette.

Incidentally this wonderful book, Agaves of Continental North America, (Gentry, 1982) is the encyclopedia and definitive reference by the man regarded as the world expert on Agave. Expensive, but well worth the price to any succulent-lover.

Lechuguilla is a poisonous range plant that has been documented to poison cattle, sheep, and goats, and--no surprise--this poisoning takes place under conditions of overgrazing. Gentry (1982, p. 157) delightfully described such mismanagement concluding that lechuguilla is "a protective agent of the range, penalizing those stockmen who, through force of circumstance or lack of foresight, decimate their resource by over-use". AMEN! The poisonous principle in lechuguilla is a saponin that causes hepatogenic or secondary photosensitization due to liver damage. References include Kingsbury (1964, ps. 56, 467-468), Sperry et al. (1964, ps. 7-8), Burrows and Tyrl 2001, 13-15), and Hart et al. (2003, 22-23).

Taxonomic treatment of Agave has been controversial. Traditionally the genus has been included in the agave family, Agavaceae, (eg. Powell, 1988), but other workers (eg. Smith, 1977) placed Agave in the lily family, Liliaceae, as an agave subfamily, Agavoideae. Incidentally, is there anything that is not controversial when it comes to plant taxonomic treatments?

Hudspeth County, Texas. June.

330. Basal rosettes of lechuguilla- Example of a cluster of rosettes, asexual modules of a genetic individual of lechuguilla. It was explained in the immediately preceding photo-caption that lechuguilla probably produces more rosettes than any other Agave species in North America. Recall from that explantion that each such rosette is a clone (= module= ramet) of the original "parent plant" which is the genet. Gentry (1982, p. 30) explained that each rosette of A. lechuguilla is a "monocarpic rosette". Each rosette flowers only once in its life (the life of that clone or module) and then dies; in fact, it begins to die as soon as the one-time flower stalk with its inflorescence begins to emerge and elongate. This condition was obvious in the flowering rosette in the cluster shown in this photograph. The inflorescence on this particular stalk was presented in the immediately succeding photograph.

With this pattern of life cycle and resource allocation, each genetic individual (the genet or actual unique plant) of lechuguilla with its ramets (rosettes) is a "multiannual" (Gentry, 1982, p. 30). Gentry's choice of terms could confuse the beginning student. Yes, the individual rosette flowers only once in its life and then promptly dies. The flowering-seed production process takes only a few weeks as flower stalk growth is extremely rapid (perhaps over a foot a day) such that this phenological development is "annual" (more like "ephemeral"). Yet it takes years (perhaps a quarter century) of reserve food storage, rosette growth, and formation of stalk primordial tissue development before flowering can be initiated. In reality each rosette is a long-lived perennial that finally flowers and then summarily dies. With asexual (vegetative or clonal) reproduction the genetically unique plant has a life span that is seemingly "endless" or "forever". The only thing annual about an Agave species is the amazing flowering and fruit production phenomenon. And that is phenomenonal.

331. Inflorescence of lechuguilla- Gentry (1982, ps. 36-46) described the Agave inflorescence. There are two basic forms of Agave inflorescence: 1) spicate or racemose typical of subgenus Littaea and 2) paniculate typical of subgenus Agave but-- as is so typical of living thing-- there are intermediate forms "which combine or bridge the two" (Gentry, 1982, ps. 37-38). The more-or-less spicate form in lechuguilla is an example of this combination form. with a Hudspeth Conty, Texas. June.

332. Inflorescence of lechuguilla in anthesis- Detailed view of individual flowers of A. lechuguilla. Pigmentation of flower organs, including filaments, apparently varies among genetic individuals of A. lechuguilla. Lechuguilla flowers are, however, always strikingly beautiful. Presidio County, Texas. June.

118. (61) Basal rosettes of lechuguilla-

333. Havard agave or Havard century plant (Agave havardiana)- Life and death simultaneously were playing out in this sexually reproducing Havard agave. After taking years (maybe several decades) to store up reserve food, grow leaves of the basal rosette, and development floral meristem this agave was in full-bloom and dying at the same time. The lowrmost leaves had already died as this plant was in anthesis and in process of exchanging gametes.

A. havardiana is in the subgenus Agave which has the paniculate form of inflorescence. A drooping or weeping juniper with fire-killed outer branches "watched" from behind as timeless Casa Grande provided a proper backdrop. Range Management has a romance all its own.

Chisos Basin, Big Bend National Park, Brewster County, Texas. June.

The conifers are members of class Gymnospermae. Gymnosperms found in the Trans-Pecos Basin and Range Region fall within three families: Pinaceae, the pine family; Ephedraceae, Mormon tea family, and Cupressaceae, the cypress family. Some of the gymnosperms of the Trans-pecos Region were treated below.

334. Mexican pinyon pine (Pinus cembroides)- Two specimens of Mexican pinyon pine growing in Green Gulch, Big Bend National Park (Brewster County, Texas). The "nut pines" have commonly been interpreted as one of four subdivisions of the soft pine group (subgenus Haploxylon; Strobus). Treatment by Harlow et al. (1979, ps. 60, 74-76) was readily followed. The so-called "nuts" are merely the naked seeds of a complicated taxon within Pinus. These seeds have served as important feeeds (ie. mast) for native and domestic animals as well food as for man. American Indians relied on pine nuts as a dietary stable for generations extending back to prehistory.

The Mexican pinyon pine of Trans-Pecos range environments is Pinus cembroides var. cembroides (Harlow et oal., 1979, p. 76; Powell, 1988, p. 51).

335. Branches and leaves of Mexican pinyon pine- Boughs with needles and terminal buds (site of apical meristem) of Pinus cembroides var. cembroides. Green Gulch, Big Bend National Park, Brewster County, Texas. June.

336. The realm and its king- A Mexican pinyon pine in the Chisos Mountains at eastern (Trans-Pecos) end of the Basin and Range physiographic province. This tree was growing with a richly diverse botanical community including rose-seed juniper, alligator juniper, Emory oak, grey oak, lechuguilla, smooth sotol or desert candle, foothill beargrass, littleleaf sumac, birchleaf mountain-mahogany, rubber rabbitbrush, Wright's threeawn, Havard's threeawns, chino grama, sideoats grama, cane bluestem, bullgrass muhly, and a few scattered plants of little bluestem. There were almost no forbs.

There are a number of sources that provided cursory treatment of Mexican pinyon pine including Coulter (1891-1894, p. 555), Sargent (1933, ps. 8-9), Vines (1960, p. 15), Correll and Johnston (1979, p. 74), Powell (1988, p. 51), and Allred and Ivey (2012, p. 40). These latter authors recognized two varieties of P. cembroides var. cembroides and var. bicolor. Powell (1988, p. 51) specified that the Mexican pinyon pine in the Trans-Pecos Region were all P. cembroides: var. cembroides which he concluded was limitd (endemic) to Texas. This conclusion obviously conflicted with the later work of Allred and Invey (2012, p. 40). The taxonomic variety P. cembroides var. cembroides was apparently previously recognized as P. cembroides var. remota called the Texas pinyon (Harlow et al., 1979, p. 76). Correll and Johnston (1979, p. 74) limited P. cembroides var. remota to the western Edwars Plateau which is to east of the Trans-Pecos vegetational area, but Powell (1988, p. 51-52) recognized P. remota as a separate species (P. ramota at the species level), with a common name of papershell pinyon, and described unique morphological features of P. remota including cones being "rather fragile" (and, presumedly, seed coats also fragile). According to Powell (1988, p.51) P. remota was "the most widespread pinyon in the Trans-Pecos".

In their treatment of the pinyons or nut pines Harlow et al. (1979, 74-76) concluded: "These pines provide a beautifully complex taxonomic puzzle". Harlow et al. (1979, p. 60) grouped the pinyon pines as one of the soft or white pines (subgenus Haploxylon or Strobus).

Mexican pinyon pine is clearly one of the defining plant species of this form of the pinyon-juniper woodland range type (SRM 504, SAF 239): Mexican pinyon pine-mixed juniper-mixed oak-grass woodland of the Trans-Pecos Basin and Range land resource area of Texas.

Various morphological parts and organs of this same specimen of Mexican pinyon pine were presented immeediately below.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October; peak standing crop of the range vegetation.

337. Trunk and boughs- Bole with characteristic bark (first, vertical slide) and several outer branches (second, horizontal slide) of Mexican pinyon pine as a defining menber of the Mexican pinyon pine-mixed juniper-mixed oak-grass woodland in the Chisos Mountains. These parts were on the tree featured in the immediately preceding slide.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October.

338. End of the twig- Terminal ends of several leaders (branches) with new apical or terminal buds and fascicles (clusters) of needles (first slide) and terminal (= distal) end of two branches, one with a mature female cone containing ripe seed (second slide) of Mexican pinyon pine in the Chisos Mountains of the Big Bend area of Trans-Pecos Texas. These leaders were on the same specimen that was introduced two slide/caption units above.

Usually there are three or, sometimes, two needles per fascicle in Mexican pinyon pine (ie, a three-needle pine) according to Correll and Johnston (1979, p. 74), Powell (1988, p.47), and Allred and Ivey (2012, p. 40). This number of needles is not diagnostic among the nut pines in Trans-Pecos Texas however because all of these species have two or three needles per fascicle (Powell, 1998, p. 47).

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October.

339. Still on the tree- Front-on view of a seed-bearing cone and the terminal portion of a young twig of Mexican pinyon pine in the Chisos Mountains of Trans-Pecos Texas. These are the same two twigs (terminal ends of twigs) presented in the immediately preceding photograph. The two slides were taken from opposite camera angles (opposite points of focus) so that the non-conebearing (upper) twig in the preceding side-view photograph was to right of the conebearing twig in this frontal-view photograph.

Allred and Ivey (2012, p. 40) noted that plants of Mexican pinyon pine are "nearly dioecious". This featured specimen was obviously a female plant.

* The azure, cobalt-blue background was the natural color of this sky. Even with Fugichrome (instead of Kodachrome) the sky as shown had the true color of the atmosphere of this arid land. God's Country!

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October. but it was yet to fall.

340. Tasty but hard eating- Two ripe and naturally fallen (tree-shed) cones with seeds of Mexican pinyon pine in a pinyon pine-mixed juniper-mixed oak-grass woodland in the Chisos Mountains of the Big Bend area of the Basin and Range physiographic province. These cones were produced by the same specimen of Mexican pinyon pine that was introduced four slide/caption units above.

It was noted above that Powell (1988, p. 51) distinguished between the two closely related (but apparently not hybridizing) species of P. cemebroides and P. remota with the latter having cones and seeds that were less durable or more fragile. The hard, tough seeds and general nature of these cones strongly suggested that they were P. cemebroides.

The seeds of Mexican pinyon pine and the Colorado pinyon pine or nut pine (Pinus edulis) (and one would have to add the papershell pinyon [P. remota] if it is a separate species) were eaten by American Indians and are still sold in grocery stores and roadside stands in some areas. Apparently the tasty seeds of Mexican pinyon are relatively hard to prepare for human consumption because they are hard-shelled (Powell, 1988, p. 51), whereas (presumedly) seeds of papershell pinyon would be thinner and less indurate.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October; seed-ripe, cone-shed stage of phenology.

341. Trunk of alligator juniper (Juniperus deppeana)- The bark of alligator juniper is separated or divided into rectangular units that somewhat resemble the scales on the back of the American alligator (Alligator mississippiensis). This juniper (it is not usually referred to as "cedar" as are many of the species of this genus) is one of the largest and, with the tell-tale bark, most distinctive of the western Juniperus species. In most of the pinyon-juniper woodland subtypes of which it is a component alligator juniper is not the most juniper nor is it typically the only Juniperus species. With its large size, however, alligator juniper has usually been regarded as a co-dominant especially when it grows in association with one of the pinyon pines. The trunks of alligator specimens are often seen to be of odd shape or form in addition to relatively large size (as shown in this individual).

Green Gulch, Big Bend National Park, Brewst4r County, Texas. June.

342. Boughs (with cones) of alligator juniper- Branches with needles and fleshy cones of Juniperus deppeana. So-called "berries" on junipers are obviously not berries because the gymnosperms bear naked seeds. Seeds of Gymnospermae members are often borne together (in groups) on a woody structure known as a cone (eg. pine cone). In case of Juniperus species, the naked seeds are encased inside a fleshy exterior (hence "berry" to the laymen) that is termed a fleshy cone or, sometimes (and less properly), as fleshy seed.

Fleshy cones and scaley leaves (needles) were displayed in more detail in the second of these slides.Green Gulch, Big Bend National Park, Brewster County, Texas. June.

343. 'gator backs in the Davis Mountains-Trunks of alligator juniper growing on a savanna form of the Mexican pinyon pine-alligator juniper-Emory oak-mixed grass-woodland range cover type in the Davis Mountains of Trans-Pecos Texas. This range had over course of about last ten years come under management of which prescribed burning was a major restoration practice.

Location note: more views of thisMexican pinyon-alligator juniper-mixed grass savanna were presented later in this chapter.

U up-U down Ranch settled by the G. S. Locke family, now Davis Mountains Preserve of The Nature Conservancy, Jeff Davis County, Texas. Early October.

344. Weeping at sundown- Drooping or weeping juniper (Juniperus flaccida) in the Chisos Mountains as seen just after sundown. The author found this fine example of a drooping junipr trunk with mature bark just as Ole Man Sun "dipped" below the Chisos peaks at end of another fine day in the Big Bend area of Trans Pecos Texas. Not the best photograph the ole Nikon FM ever took, but students get a good example of this picturesque junipr nonetheless.

Weeping or drooping juniper is the least abundant of three major Juniperus species in this area, but it is a unique, distinctive, and abundant enough species to occupy a well-earned presence in this treatment of a diverse, lovely range cover type.

The defining, namesake (for both common and scientific names) feature of this juniper was presnted in greater detail in the next three slide/caption units.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October.

345. The right combination- "Drooping" smaller branches of weeping cedar (= weeping juniper, drooping cedar) provided a foliaceous backdrop for sideoats grama, the Texas State Grass, in a Mexican pinyon pine-mixed juniper-mixed oak-grass woodland in the Chisos Mountains of the Big Bend area of Texas.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October.

346. Nothing to be droopy about- Examples of "hanging" terminal branches and fleshy female cones or fleshy seeds on drooping or weeping juniper which is one of three important Juniperus species in a Mexican pinyon pine-juniper-mixed oak-grass woodland in the Chisos Mountains of the Texas portion of the Basin and Range physiographic province. These plant parts were on the same tree that was presented immediately above that was accompanying sideoats grama, the State Grass of texas.

Weeping juniper is the least common of three major Juniperus species in the Big Bend area, but with its "hanging" branches it is unquestionably the most unique of the three junipers. It is just one of numerous plant species that comprises this diverse and amazingly productive range type.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October.

347. Drooping details- The fleshy female cones or fleshy seeds of weeping or drooping juniper in the Chisos Mountains of Trans-Pecos Texas shown at a closer distance (as a larger image). These organs were growing on the same plant whose parts were featured in the two immediately preceding slide/caption units.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October.

348. Time for a unique one- Arizona cypress (Cupressus arizonica) is the sole species of this genus that grows in the Trans-pecos Basin and Range Region. With Juniperus species, Cupressus arizonica rounds out representation of the cypress family, Cupressaceae. Arizona cypress ranges from the northern states of Mexico westward to California and as far north and east as New Mexico, but its only natural occurrence in Texas is in the Chisos Mountains of Brewster County.

Arizona cypress has much value as a native ornamental (and is grown far beyon its species range). Shown here was one small terminal branch (first slide) and mature though yet unopened cones (second slide).

Brewster County, Texas. Late October.

349. Cypress cones- Opening cones of Arizona cypress. The cones of Cupressus species are more like some members of the redwood or bald cypress family, Taxodiaceae, than they are like some members of Cupressacea such as Juniperus species which, as shown above, have fleshy cones. At maturity, cones of Arizona cypress dehisce or split open to release the dry seeds contained inside as seen in these two photographs..

Brewster County, Texas. Late October.

350. Opened cypress cone-A ripe or mature cone of Arizona cypress that has dehisced to reveal (barely in this slide) the dry, naked seed inside. This specimen was laid up against the young, curling bark on the upper trunk of the tree. Brewster County, Texas. Late October.

351. Trunk of an oldster-The bole with characteristic old bark of a mature Arizona cypress. Brewster County, Texas. Late October.

352. Youthful skin- Bole of a younger Arizona cypress with younger bark (first slide) and details of this curled bark (second slide). Brewster County, Texas. Late October.

The following short section was devoted to some of the more important scrub oaks of the Trans Pecos Region, especially the Chisos Mountains. An ideal, up-to-date manual of woody plants of this floristically rich area was that of Powell (1988). It was highly recommended. Also strongly recommended was the beloved and timeless reference by Vines (1969).

353. Major oaks of the Chisos Mountains- Two species of oak were "put on parade" in this photograph taken in Green Gulch, Big Bend National Park. The tree on the left (and either basal heterophyllus shoots= "suckers" or a set of seedling shoots to its left and right) were Emory oak (Quercus emoryi); the shrub on the right was gray oak (Q. grisea). These two species are generally regarded as the two dominant oaks of mountains in the Trans-Pecos area (Powell, 1988, ps. 21-22). June.

354. Details of Emory oak- Bark, leaves, and fruit of Emory oak were displayed in this slide. Small shoot to left of big trunk was either a secondary shoot (perhaps heterophyllus shoot sprouting from basal trunk or roots) or an Emory oak seedling. Emory oak is the dominant Quercus species that develops a tree form in most Trans-Pecos Ranges like the Chisos Mountains. Green Gulch, Big Bend National Park, Brewster County, Texas. June.

355. Emory oak (Quercus emoryi)- Leaves and acorns on a large Emory oak in the Davis Mountains of Trans-Pecos Texas. Emory oak is in the red or black oak subgenus, Erythrobalanus, species of which require two full growing seasons (years) for acorn production. Acorns are, of course, one of the major fruits known as mast, "nuts, acorns, and similar products which are consumed by animals" (Jacoby, 1989). Species from native birds and ruminants to man and his livestock use acorns as a staple of their diets.

Jeff Davis County, Texas. June.

356. Gray oak- Gray oak is the dominant species of scrub oak in most of the major mountain ranges throughout the Trans-Pecos Basin and Range area. This specimen was the plant growing to the right of the Emory oak tree in the two photographs just before the preceding photograph of Emory leaves and acorns.

Green Gulch, Big Bend National Park, Brewster County, Texas. June.

357. Leaves of gray oak (Quercus grisea)- Leadaers with leaves of the specimen of gray oak shown in the immediately preceding photograph.Gray oak is in the white oak subgenus, Leucobalanus, species of which require only one full growing season for production of an acorn crop.

Green Gulch, Big Bend National Park, Brewster County, Texas. June.

358. Vasey oak or Vasey shin oak (Quercus vaseyana= Q. pungens var. vaseyana)- Numerous leaders of Vasey oak bearing a heavy nut crop. Brewster County, Texas. Mid-September, mature-fruit stage.

359. Leaves and acorns of Vaey oak- Vasey oak is in Leucobalanus subgenus the acorns of which develop to maturity in one year. Brewster County, Texas. Mid-September, mature-fruit stage.

360. Vasey pungent cluster- Group of acorns of Vasey oak. Acorns of Q. pungens var. vaseyana are typically borne in cluster-like groups. Brewster County, Texas. Mid-September, mature-fruit stage.

361. Baby leaves above baby girls- New leaves and young pistillate catkins of Lacy oak (Quercus lacyi= Q. glaucoides) against a blue spring sky.

Brewster County, Texas. Mid-March.

362. Leader of Lacy oak- With backdrop of bright autumn sky the two distal-most nodes (last two growing seasons of growth) of Lacy oak portrayed characteristic leaves plus some acorns.

Brewster County, Texas. Mid-September, mature-fruit stage.

363. Leaves and acorns of Lacy oak- Detail of leaves and acorns of Lacy oak. This species is in the Leucobalanus subgenus so nuts grow to maturity in a single year (one warm-growing season).

Brewster County, Texas. Mid-September, mature-fruit stage.

364. Lacy concentrate- Acorn of Lacy oak showing fruit characteristics of this species. The hgig-nutrient concentration of acorns qualifies this nut as a concentrate range feed.

Brewster County, Texas. Mid-September, mature-fruit stage.

365. Two "pals" in the oak-pinyon-juniper woodland cover type- A Texas madrone, known also as naked Indian and lady's leg, (Arbutus texana= A. xalapensis= A. xalapensis. var. texana) and, behind the madrone, alligator juniper. Texas madrone typically grows as an individual tree or shrub or, infrequently, in small colonies. This species is not a dominant or even an associate species, but it is a woody component and characteristic species of oak-pinyon-juniper woodland range in the Trans-Pecos Basin and Range area. Texas madrone (like alligator juniper) is also a characteristic species in range plant communities besides the pinyon-juniper cover type. An example includes ecotones between a mosaic of encinal oak and pinyon-juniper woodland and ponderosa pine cover types which was the case for these two trees. Texas madrone does "stand out" in the any woodland crowd as rangemen would expect of a lady's leg or a naked Indian.

Texas madrone is in Ericaceae, the heath or heather family, one of the characteristics of which is smooth, colorful bark on often bent or curving shoots and limbs (again, like a lady's leg or naked Indian).

Guadalupe Mountains, Guadalupe National Park, Culbertson County, Texas. June.

366. Two "legs" in the oak-pinyon-juniper woodland cover type- A "pin-up" photograph of Texas madrone or lady's leg (right) and an alligator juniper (left) showing characteristic bark of these two species that occur on oak-pinyon-juniper woodland range. Close-up of the two trees introduced in the immediately preceding photograph. These two specimens were growing in the Guadalupe Mountains in transition range vegetation between encinal oak/ pinyon-juniper woodland and ponderosa pine forest.

Leaves of ericaceous species are, like their bark, distinctive and possessing unique features. Leaves of most members of the Ericaceae are relatively large, thich, and highly cutinized. Ericaceous leaves such as those of Arbutus species have traditionally been described as "broad-schlerophyllus" following Cooper (1922) who first applied the term to Clifornia chaparral vegetation.

Guadalupe National Park, Culbertson County, Texas. June.

367. Blooming madrone- Shoots of Texas madrone or naked Indian at full-bloom stage. Williamson County, Texas. March.

368. Sexual shoots- Two shoots of Texas madrone at peak bloom. Also examples of leaf characteristics of this ericaceous shrub. Williamson County, Texas. March.

369. Flowers of Texas madrone- Details of flower cluster and individual flowers of Texas madrone or lady's leg. This was a good example of the basic floral features of the Ericaceae as viewed on the range. Williamson County, Texas. March.

370. Time for the fruit- Leaders with leaves and fruit of Texas madrone, naked Indian, or lady's leg. The fruit type of Texas madrone is a fleshy berry with two to several ovules per locule (Diggs et al., 1999, p. 582).

Big Bend National Park, Chisos Mountains, Brewster County, Texas. Mid-October; fruit-ripe phenological stage.

371. Shinning fruit and bark- Shoot of Texas madrone with fruit-bearing leader (first slide) and cluster of fruit with leaves of Texas madrone (second slide). The author has seen more shapely legs on college coeds (but not all of those legs were on ladies).

Big Bend National Park, Chisos Mountains, Brewster C phenological stage. ounty, Texas. Mid-October; fruit-ripe.

372. Branches of littleleaf sumac (Rhus microphylla) in full-fruit- Leaders of littleleaf or desert sumac (first photograph) and details of leaves and fruit of the same (second slide). The fleshy fruit of Rhus species is a drupe: the fruit type in which the outer layer or skin is the exocarp, the fleshy layers are mesocarp, and the bone-like seed coat is the endocarp; endocarp and seed constitute a pyrene (the stone or pit). Hence, drupes are stone fruits or pit fruits (Smith, 1977). This woody species is well-adapted to xeric environments and is widely distributed on harsher habitats such as drier or shallower soils in the Great Plains as well as basins and bajadas of the Chihuhuan Desert. Desert sumac is often common of tobosagrass (Hilaria mutica) swales or "flats" in the semidesert grasslands.

Drupes are sometimes cooked in hot water to make "hillbilly lemonade". Beats a job in the eye, but this author recommends the "real stuff" (or tea or coffee or milk or cold water or …; you get the picture).

Davis Mountains, Brewster County, Texas. June.

373. Lanceleaf sumac (Rhus lanceolata= R. copallina var. lanceolata)- Lanceleaf sumac is one of the Rhus species that can grow into tree form and size (or a large, spreading shrub) as evidenced by this specimen that was at peak bloom in the Davis Mountains of Trans-Pecos Texas (Brewster County). June.

374. Leaves and inflorescences of lanceleaf sumac- This Rhus species is of limited browse value for livestock (generally Poor feed value) except for goats and it is of somewhat higher browse value (roughly Fair) for native browsers like deer, but the drupe fruits can be excellent for birds like upland game species. All visible parts of this woody species appeared to this author to have potentially high ornamental value, especially for native plant purists.

The inflorescence type is a panicle.

Davis Mountains, Brewster County, Texas. June..

375. Evergreen sumac, tobacco sumac, or lentisco (Rhus virens subsp. virens)- Not much attention has been paid to this sumac as a range plant. In Important Western Browse Plants Dayton (1931, p. 97) cited previous work that found evergreen sumac "to be a pioneer in the vegetation of limestone ledges in west Texas, forming a protection for other species which occupy more slowly…" and therefore being important in watershed protection.

The adjective "evergreen" comes from the supposed characteristic of evergreenness, but leaves of this subspecies and toughleaf sumac (R. virens subsp. choriophylla) frequently turn red or brown in autumn. Leaves are extrmely shiny and bright. The adjective "tobacco" was derived from reports that Indians like the Commanches cured leaves and used them as a substitute for or mixed with tobacco to smoke in their pipes. The fruits of all Rhus species can be used to make a refreshing drink (often termed "lemonade") by steeping in hot water and subsequent cooling. Good for college freshmen who will (do) try any- and everything. Returning to the namesake "tobacco" and sticking with college students, it should be pointed out that smoking of Rhus leaves is likely less toxic than most else they smoke, snort, guzzle, shoot, poke, prod, pump, hump, or otherwise imbibe in.

Presidio County, Texas. June.

376. Phytoparasite in the Chisos- Rough or boll American mistletoe (Phoradendron bolleanum= P. hawksworthii) parasitizing a juniper (Juniperus sp.). Add to the multi-layers of the oak-Mexican pinyon pine-juniper woodland an epiphyte layer, and a parasitic one at that. Parasitism is one of the important interactions among organisms on ranges. In context of range plants and vegetation your author included important parasitic throughout this publication. This example continued that tradition.

Mistletoes have been extensively studied by forest pathologists, but the mistletoe featured here is not one of the major economically important species.

Mistletoes like the Phoradendron species are known as the true or leafy mistletoes (in contrast to the dwarf mistletoes that are far more common on conifers).

Green Gulch, Big Bend National Park, Brewster County, Texas. June.

377. Plant parasitism in the Chisos- Rough or boll American mistletoe parasitized (and probably killed) this juniper on an oak-Mexican pinyon pine-juniper woodland range. The second slide showed the sites of shoot emergence and of penetration of haustorium which is the projection of hyphae that function as the absorbing organ into tree cells. Haustorial strands spread laterally along conifer shoots (branches) and send down sinkers deeper into shoots to absorb nutrients of the host conifer (Agrios, 1988, ps. 618-620).

Green Gulch, Big Bend National Park, Brewster County, Texas. June.

378. Chinograss or chino grama (Boutelous ramosa)- This is the dominant range plant on much of the foothill semidesert grassland and Chihuhuan Desert-semidesert (Chihuhuan) grassland ecotone range types and it is an important (often co-dominant) species in the sotol-lechuguilla-grama grassland range type. Chino grama remains a major species in the herbaceous layer in the oak-Mexican pinyon pine-juniper woodland cover type where it is typically the most widespread grass. In the oak-pinyon pine-juniper woodland individual plants of chino grama attain considerably less size, especially fewer shoots, than on grassland or shrub-savanna range types.

The rocky land surface shown here was typical of much of the oak-Mexican pinyon pine-juniper woodland. There were not relict or reference areas to which this soil surface could be compared. This surface condition was very similar to stone pavement on floor of the bajadas and basins of Chihuhuan Desert below the foothills of Chisos Mountains where this photograph was taken.

Green Gulch, Big Bend National Park, Brewster County, Texas. June, early estival stage prior to onset of summer rainy period and, therefore, prior to this year's "green-up".

379. Colony of spidergrass or spider threeawn (Aristida ternipes= A. trnipes var. ternipes)- This is one of the more distinctive (ie. less easily confused) of the perennial Aristida species. It is also one of the more abundant threeawns in mountains of the Trans-Pecos area and, indeed, throughout much of the immense Chihuhuan-Sonoran Deserts super-region. While spidergrass is distinctive (panicles were shown below), and not as readily confused as most of the semiarid-arid Aristida species, this does not preclude mix-ups, nomenclatural inconsistency, continuing analysis and re-analysis of specimens, and spirited contradictions in taxonomy of A. ternipes (along with most other Aristida speceis).

Some of the confusion in the literature on Aristida was described in detail elsewhere herein, especially in regards the numerous Aristida species in the Sonoran Desert chapter (Shurblands), so details were not "re-hashed" in this photo-caption. Various authorities who tried to "straighten out the mess" (and wound up contributing to the mess as well as to Aristida taxonomy) in southwestern North America included Silveus (1933), Hitchcock and Chase (1951), Gould (1951), Gould (1975), and Powell (2000). As of this writing the latest "official" treatment (but if the past is any indication not the last of such) on Aristida was that of Allred (in Barkworth et al., 2003, ps. 330-335). Also worthy of reference was the well-structured work of Powell (2000, ps. 239-254 passim, esp. 244-246).

The latest taxonomic treatments viewed A. ternipes and A. hamulosa as a "species pair" and "cospecific" as A. ternipes var. ternipes and A. ternipes var. hamulosa (see Powell, 2000, ps. 245-246 for discussion and citation of original sources).

Specimens of spidergrass presented in this and the next two slides were representatives of the dominant herbaceous species in the understorey of upper elevation oak-Mexican pinyon pine-juniper woodland range in the Chisos Mountains.

Green Gulch, Big Bend National Park, Brewster County, Texas. June, seed-ripe to seed shatter phenological stages.

380. Specimen of spidergrass- This individual of Aristida ternipes was a good example of the habit (general appearance) and some of the gross physical details of its species. The tortuous shape of upper leaves and panicle branches could have easily invoked metaphorical comparison to a spider-like configuration.

Green Gulch, Big Bend National Park, Brewster County, Texas. June, seed-ripe to seed-shatter stage.

381. Examples of Havard's legacy- Two plants of Havard's threeawn (Aristida havardii) in the first slide and closer-in view in the second slide of the Havard's threeawn plant at left in the first slide that were growing in the understorey of a Mexican pinyon pine-juniper-mixed oak-grass woodland in the Chisos Mountains of Trans-Pecos Texas.

Aristida species are primarily species of disturbance, including overgrazing, and have traditionally been interpreted as ecological invaders or, at best, increasers from a plant succession standpoint. There are exceptions to every rule (except the rule about exceptions) and A. havardii and A. arizonica (treated immediately below) are exceptions. These two Aristida species are decreasers (climax dominants) on most, if not all, range sites within the Mexican pinyon pine-juniper-mixed oak-grass woodland range type.

In the two views presented here, sideoats grama was present immediately behind the featured plants of Havard's threeawn. Presence of sideoats grama, which is a climax midgrass (= a decreaser species) on this habitat, provided empherical support for the preceding statement that Havard's threeawn is a decreaser on this range site. Palatability may be another matter, but as regards adaptation to this range environment Havard's threeawn is a major herbaceous member of the climax range vegetation.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October; peak standing crop, seed-ripe to seed-shatter stage.

382. Another example of Havard's legacy- One plant of Havard's threeawn shown in its aboveground entirety (first slide) and at closer camera distance for details of shoots (second slide) growing in the understorey of a Mexican pinyon pine-juniper-mixed oak-grass woodland range in the Chisos Mountains in the Big Bend area of Texas. Immediately behind this plant was cover of sideoats grama. Both of these eragrostoid grass species are decreasers in this range plant community.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October; peak standing crop, seed-ripe to seed-shatter stage.

383. A taste of Arizona in Trans-Pecos Texas- General view showing overall habit of aboveground (first slide) and closer-in view of shoots (second slide) of a plant of Arizona threeawn (Aristida arizonica). These two specimens were growing in asssociation with the specimens of Havard's threeawn presented (and ecologically treated) immediately above. As was explained for Havard's threeawn, Arizon threeawn is a climax species (a decreaser) in the herbaceous understorey of a Mexican pinyon pine-juniper-mixed oak-grass climax woodland community. Both Havard's and Arizona threeawns are members of this range plant community (= potential natural vegetation) that developed in the Chisos Mountains of Trans-Pecos Texas.

As a general rule, Aristida species are not highly palatable to most range animals (espeically the ungulates) and, perhaps as a consequence of that fact, the threeawns have been regarded generally as ecological (successional) invaders or, at best, increasers. Havard's threesawn and Arizona threeawn are two exceptions to that general rule. Again, these two cespitose, perennial, eragrostoid grasses are decreasers in pinyon pine-juniper-oak-grass woodland range type of the Trans-Pecos Basin and Range vegetational area of Texsas, palatablility (or lack thereof) notwithstanding.

Green Gulch, Big Bend National Park, Brewster County, Texas. Early October; peak standing crop, seed-ripe to seed-shatter stage.

Taxonomic referral- The authority for Aristida species of the Texas, the Trans-Pecos, portion of the Basin and Range physiographic province is (as of this writing) Powell (2000, ps. 239-254). The recognized authority on taxonomy and nomenclature of the North Amereican, especially for southwestern North America, Aristida is Allred in Barkworth et al. (2003, ps. 315-342). There is perhaps no other North American grass genus that has been more subject To the eternal tug of war between "lumpers" and "splitters" and to use of taxonomic variety than in the case of Aristida.

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Southern and Middle Rocky Mountain Forests - IB (Including Regionally Related Range Types)

Ponderosa Pine Forests and Associated Types or Subtypes

Arizona Ponderosa Pine Forest Range

Southern and Middle Rocky Mountain Forests - IB
(Including Regionally Related Range Types)