tor graminoids in these more southerly locations rather 

 than Carex geyeri (see the POTR/SYOR/CAGE c.t. 

 section). The type usually occurred at the intermediate 

 and upper elevations ranging from 7,500 to 9,100 ft 

 (2 290 to 2 770 m). Although the type was found most 

 frequently on gentle slopes, it does not appear to be 

 restricted by either slope exposure or soil parent 

 material. 



The characterizing species for the type are the conspic- 

 uous Juniperus communis in the shrub stratum and the 

 dominant graminoids C. geyeri or S. occidentalis or both 

 in the herb stratum (fig. 4). In central and southern 

 Utah, C. rossii usually replaces C. geyeri in the associa- 

 tion. Juniperus communis generally grows as distinct 

 low, compact clumps widely scattered beneath the aspen 

 canopy. These clumps frequently are interspersed with 

 Symphoricarpos oreophilus and Berberis repens, which 

 may form a substantial part of the shrub layer. The herb 

 layer usually is fairly simple. In addition to the typify- 

 ing graminoids, such forbs as Astragalus miser, 

 Geranium viscosissimum, Lupinus argenteus, Achillea 

 millefolium, and Thalictrum fendleri may grow in sub- 

 stantial amounts. Conifers, usually Pinus contorta or 

 Pseudotsuga menziesii, are occasionally present in minor 

 amounts. 



Stands within this type are ordinarily in a stable 

 aspen condition. In those cases where conifers appear 

 able to invade, the stands may be a successional stage 

 within the Abies lasiocarpa/J. communis, A. lasiocarpa/ 

 B. repens, or possibly P. menziesii/B. repens habitat 

 types described by Mauk and Henderson (1984). Exces- 

 sive livestock grazing will likely lead to substantial 

 increases in the amount of Taraxacum officinale, 

 A. miser, A. millefolium, and possibly J. communis at 

 the expense of the more palatable and less tenacious for- 

 age species. 



Although the average basal area produced by aspen 

 within this type appears moderate, its site index is low. 



Basal area of the 11 stands sampled for productivity 

 ranged from 47 to 234 ft^/acre (10.9 to 53.6 m^/ha) and 

 averaged 146 ft'/acre (33.5 m-/ha). This basal area was 

 98 percent aspen. Site index at 80 years for the aspen 

 ranged from 23 to 68 ft (7.0 to 20.7 m) and averaged a 

 low 45 ft (13.7 m). Aspen reproduction within these 

 stands was also low, averaging only 896 suckers/acre 

 (2 215/ha). Two-thirds of these suckers were in the 1- to 

 4.6-ft (0.3- to 1.4-m) height class. The amount of under- 

 growth production within this type is relatively low and 

 rather evenly distributed among the different vegetation 

 categories. Total production ranged from 141 to 1,031 

 lb/acre (158 to 1 158 kg/ha) and averaged only 597 

 lb/acre (670 kg/ha). This consisted of 42 percent grami- 

 noids, 4 percent forbs, and the remainder was shrubs. Of 

 the undergrowth, 53 percent was in the highest forage 

 suitability class, and almost 10 percent was in the 

 lowest class. The type has relatively low potential for 

 livestock forage production. Value as habitat for wildlife 

 appears only moderate because of its modest amount of 

 structural diversity. 



Aspen communities with a low shrub layer dominated 

 by J. communis have been reported from two separate 

 areas in Wyoming. Wirsing and Alexander (1975) identi- 

 fied a P. tremuloides/C. geyeri habitat type on the 

 Medicine Bow National Forest in southeastern Wyoming 

 similar to our type in that J. communis was the prin- 

 cipal shrub and C. geyeri characterized the herbaceous 

 layer. However, their type differed by the absence of 

 S. oreophilus and abundance of Arnica cordifolia and 

 Osmorhiza depauperata. A P. tremuloides/J. communis 

 community type was described for western Wyoming 

 (Youngblood and Mueggler 1981) in which J. communis 

 dominated the shrub layer, but differed from our type 

 by the prominence of the associated shrub Shepherdia 

 canadensis and by the lack of characterizing graminoids 

 in the rather depauperate herbaceous layer. 



Figure 4.— The Populus 

 tremuloides/ Juniperus 

 communis/Carex geyeri c.t. 

 is prominent in the Uinta 

 [VIountains of northeastern 

 Utah. In this typical stand 

 near the Kaler Hollow Guard 

 Station on the Ashley 

 National Forest, 

 J. Communis Is the 

 conspicuous low shrub. The 

 herbaceous growth consists 

 primarily of such graminoids 

 as C. geyeri and such forbs 

 as Astragalus miser and 

 Lupinus argenteus. 



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