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West Elk Mine <br />by aspen at higher elevations. The oakbrush community occurs primarily on upland areas <br />between 2,100 and 2,400 m (7,000-8,000 ft.), extending to as low as 1,800 m (6,000 ft.) on steep, <br />north-facing slopes and along narrow valleys and gullies. The oakbrush community intergrades <br />with the xeric mountain shrub community along transitions between coo], north-facing slopes <br />and warm, steeper south-facing slopes. The oakbrush community location which was sampled is <br />located on soil mapping unit number 6. <br />Shrubs in this location are unusually dense and short, a condition that is not typical of the type in the <br />environmental study area. This physiognomy may have been the result of past human disturbance, <br />possibly a fire, which led to extensive resprouting by shrubs over the face of this slope or other <br />edaphic factors maybe operating which contribute to the unusually high shrub density. <br />The shrub canopy consisting of five species, provided 105 percent cover. The shrub stratum was <br />composed of a tall, 3 m (9 ft.) layer dominated by servicebetry (27 percent cover) and Gambel oak <br />(47 percent cover). A shorter, lm (3 ft.) layer was dominated by snowberry and chokecherry. The <br />taller species did not appeaz to inhibit the development of understory species, with the result that a <br />dense, multi-layered shrub stratum occurred throughout this site. An unusual aspect of this site was <br />the low stature, but relatively high density of chokecherry. One species of mature tree, Rocky <br />Mountain juniper (Juniperus scopulorum), was observed along the 100-meter transect line, <br />contributing three percent cover. <br />Eighteen herbaceous species {three graminoid, l5 forbs) were sampled along the 100-meter transect, <br />providing an average cover of 39 percent. Height of the herbaceous stratum ranged from 15-SO cm <br />(5-16 in.). Elk sedge (Carex geyen~ was the most important graminoid species observed; providing <br />14 percent cover and occurring in 80 percent of the sampled areas.. No strongly dominant forbs <br />were recorded. The highest importance values were calculated for chickweed (Stellaria crassifolia), <br />and American vetch (Nitta americans), based primarily on their relatively high densities. No forb <br />species provided average cover over 10 percent. A deep, continuous litter layer was observed <br />throughout this type, reducing the erosion hazard. <br />One significant variant within the oakbrush vegetation community is the mature Gambel Oak <br />vegetation type. It is distinguished by the dominance of Gambe] oak and the frequently lazge size of <br />oak individuals (5-6 m, IS-20 ft. in height). This community variant is restricted to the bottom of <br />permanent stream drainages. It ranges from 1,950-2,100 m (6,500-7,000 ft.) in elevation in the-study <br />azea. Representative areas occur along the drainages of the East and Dry Forks of Minnesota Creek <br />and Sylvester Gulch. <br />The oak stand sampled is located on soil mapping unit number X26. The shrub stratum was divided <br />into two layers consisting of seven species and provided 83 percent cover. The tall layer (ranging <br />from 2 to 5 m) (6-16 ft.) consisted entirely of Gambel oak. The secondary layer ranged from 0.5-1 <br />m (2.5 - 3 ft.) in height.. Gambe] oak was the most important species of the type, contributing 60 <br />percent cover. <br />Eighteen herbaceous species (two graminoid, 16 forb species) were sampled along the 100-meter <br />intercept line, providing 19 percent average cover. Height of the herbaceous stratum ranged from 5- <br />20 cm (2-8 in.). Kentucky bluegrass (Poa pratensis) was the most important graminoid species, , <br />providing seven percent average cover, and occurring in 50 percent of the sampled areas. An <br />annual species, littleflower collinsia (Collinsia parviflora), was the most important species, <br />2.04-137 Bruised Apn17004 PR/0 <br />