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West E[k Mrne <br />primarily because of its high density. Of the 18 herbaceous species sampled, five represented <br />common pasture or exotic weed species. These species include Kentucky bluegrass, dandelion <br />(Taraxacum officinale), cheatgrass (Bromus tectorum), sweet clover (Melilotus officinalis), and <br />mountain pepperweed (Lepidium montanum). Litter cover was nearly continuous, and consisted <br />almost entirely of Gambe] oak leaves. This deep litter layer may have an inhibitory effect on the <br />establishment of some species, which may explain the scattered distribution of herbaceous species <br />and low total cover. <br />Aspen <br />The aspen community is the second most prevalent vegetation community in the study area, and <br />is distinguished by the presence of mature aspen trees, ranging in height from 5-10 m (15-30 ft.). <br />A shrub understory ranging in height from 2-5 m (6-15 ft.) is present in most aspen stands. <br />Representative understory shrub species include chokecherry, serviceberry, and Rocky Mountain <br />maple (Acer glabrum). The aspen community is found on much of the southeastern portion of <br />the study azea, generally occupying areas above 2,400 m (8,000 ft.) in elevation. This vegetation <br />community extends to lower elevations primarily on north-facing slopes and along the bottom of <br />drainages. It reaches its lowest occun-ence at about 2,040 m (6,800 ft.) on steep, north-facing <br />slopes in Sylvester Gulch. <br />The representative aspen community sampled in Sylvester Gulch is located on soil mapping unit <br />number X31. The tree stratum, consisting entirely of aspen, provides 50 percent cover. The <br />calculated maximum possible importance value for aspen indicated it was the only tree species <br />present. <br />The shrub stratum within this representative aspen community consisted of six species and <br />provided 104 percent cover (cover in excess of 100 percent was due to overlapping coverage <br />among species along the intercept line). The shrub stratum was divided into two layers. The tall <br />layer (4-7 m, 12-20 ft.) consisting of chokecherry, Gamble oak, serviceberry and aspen was <br />dominated by chokecherry and s~rviceberry. The shorter layer (0.5-1.5 m, 1.5-4.5 ft.) consisting . <br />of snowberry and Wood's rose (Rosa woodsii), was dominated by snowberry. <br />Fifteen species (two grass or grass-like species and 13 forbs) were sampled in the herbaceous <br />stratum of this aspen community, collectively providing 24 percent cover. Height of the herbaceous <br />stratum ranged between 10 and 30 cm (4 and 12 in). Elk sedge was the most important graminoid <br />species of this type providing four percent cover occurring in 60 percent of the sampled azea. The <br />most important forb species was sweet Cicely (Osmorhiza obtusa) providing 10 percent cover and <br />occurring in 100 percent of the sampled area. Almost continuous litter cover was observed <br />throughout the site, consisting lazgely of aspen and shrub leaves. <br />Douglas Fir <br />The Douglas fir vegetation community is distinguished by the presence of mature Douglas fir <br />(Pseudotsuga menziesii) trees ranging in height from nine to 30 m (30-100 ft.). The shrub <br />understory has variable cover and density. Shrub cover is sparse under mature Douglas fir trees <br />on steep slopes. Shrub cover increases on more level sites and where Douglas fir is scattered. <br />2.(]4-138 Rrvised April ?004 PR10 <br />