2006-06-02_PERMIT FILE - C1980007 (5)

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west ttx Nrt„e by aspen at higher elevations. The oakbrush community occurs primarily on upland areas • 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, north-facing slopes and along narrow valleys and gullies. The oakbrush community intergrades with the xeric mountain shrub community along transitions between cool, north-facing slopes and warm, steeper south-facing slopes. The oakbrush community location which was sampled is located on soil mapping unit number 6. Shrubs in this location aze unusually dense and short, a condition that is not typical of the type in the environmental study area. This physiognomy may have been the result of past human disturbance, possibly a fire, which led to extensive resprouting by shrubs over the face of this slope or other edaphic factors may be operating which contribute to the unusually high shrub density. The shrub canopy consisting of five species, provided 105 percent cover. The shrub stratum was composed of a tall, 3 m (9 ft.) layer dominated by serviceberry (27 percent cover) and Gambel oak (47 percent cover). A shorter, lm (3 fr.) layer was dominated by snowberry and chokecherry. The taller species did not appeaz to inhibit the development of understory species, with the result that a dense, multi-layered shrub stratum occurred throughout this site. An unusual aspect of this site was the low stature, but relatively high density of chokecherry. One species of mature tree, Rocky Mountain juniper (Juniperus scopulorum), was observed along the 100-meter transect line, contributing three percent cover. Eighteen herbaceous species (three graminoid, 15 forbs) were sampled along the 100-meter transect, providing an average cover of 39 percent. Height of the herbaceous stratum ranged from 15-50 cm (5-16 in.). Elk sedge (Carex geyeri) was the most important graminoid species observed, providing 14 percent cover and occurring in 80 percent of the sampled areas. No strongly dominant forbs were recorded. The highest importance values were calculated for chickweed (Stellaria crassifolia), and American vetch (Vida americana), based primarily on their relatively high densities. No forb species provided average cover over 10 percent. A deep, continuous litter layer was observed throughout this type, reducing the erosion hazard. One significant variant within the oakbrush vegetation community is the mature Gambel Oak vegetation type. It is distinguished by the dominance of Gambel oak and the frequently large size of oak individuals (5-6 m, 15-20 ft. in height). This community variant is restricted to the bottom of permanent stream drainages. It ranges from 1,950-2,100 m (6,500-7,000 ft.) in elevation in the study azea. Representative areas occur along the drainages of the East and Dry Forks of Minnesota Creek and Sylvester Gulch. The oak stand sampled is located on soil mapping unit number X26. The shrub stratum was divided into two layers consisting of seven species and provided 83 percent cover. The tall layer (ranging from 2 to 5 m) (6-16 ft.) consisted entirely of Gambel oak. The secondary layer ranged from 0.5-1 m (2.5 - 3 ft.) in height. Gambel oak was the most important species of the type, contributing 60 percent cover. Eighteen herbaceous species (two graminoid, 16 forb species) were sampled along the 100-meter intercept line, providing 19 percent average cover. Height of the herbaceous stratum ranged from 5- 20 cm (2-8 in.). Kentucky bluegrass (Poa pratensis) was the most important graminoid species, providing seven percent average cover, and occurring in 50 percent of the sampled azeas. An . annual species, littleflower collinsia (Collinsia parv~ora), was the most important species, 1.04-138 Revised Navember7004 PRIG