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<br /> <br /> <br />type. In the more mesic sites, Aspen stands intergrade with mountain shrub communities. Mountain <br />shrub communities invade dying aspen stands as the canopy opens up (disease or drought are the main <br />causes). This invasion is short lived as young aspen trees soon overtop the shrub species that then re- <br />initiates the cycle. <br />Besides the occasional road and small pockets within larger stands of sagebrush that are subject to <br />prescribed burns, the mountain shrub community exhibits no evidence of disturbance in the recent past. <br />Little rangeland improvement is gained through prescribed burns since the majority of dominant shrub <br />species re-sprout immediately after fire and the thinning benefits are short-lived. Except where this <br />community is over-mature and therefore, largely impenetrable, it provides excellent cover, forage, and <br />browse for resident deer and elk herds as evidenced by numerous and extensive observations (both <br />visual and aural) during the course of vegetation field work. <br />3.5.2 Mountain Shrub Reference Area <br />The Mountain Shrub reference area is located on the ridgeline east of Wilson Creek and includes the <br />Mountain Shrub Reference Area used for the Colowyo Mine. Cedar Creek has expanded the boundaries <br />of the established Colowyo reference area to include the southeast-facing slope of the ridge thus <br />accounting for the extensive xeric sub-type encountered in the study area. Review of Table V7 and Chart <br />V1 indicates that the average vegetation cover of the Mountain Shrub reference area was 62.75%. Litter <br />and rock provided an average of 26.3% and 0.5% of the ground cover, respectively, while bare ground <br />exposure averaged 10.5%. The dominant plant species were mountain snowberry, mountain big <br />sagebrush, bluegrass, cheatgrass, and tailcup lupine (Lupins caudatus) with 15.8%, 12.5%, 6.6%, <br />5.2% and 3.0% of the ground cover, respectively. Perennial plants (excluding noxious weeds) <br />contributed 88% of the total plant cover (55.1% average cover) while annual species and noxious weeds <br />contributed 12% and 0.0% of the composition, respectively. Perusal of Table V10 indicates that a total <br />of 7 perennial species contributed at least 3% relative cover or composition (3% is the typical lower limit <br />for plant diversity bond release evaluations). Two of those species were grasses, two were forbs, and <br />the remaining three were shrubs. <br />Review of Tables V11 and Chart V3 indicates that the average herbaceous production of this area in <br />2005 was 804 pounds per acre, oven-dry weight. Eighty-two percent (663 pounds per acre) of the total <br />herbaceous production is attributable to perennials, with grasses contributing 588 lbs./acre and forbs <br />providing 75 lbs./acre. Eighteen percent (141 pounds per acre) of the total production is attributable to <br />CEDAR CIRR1EIEKAMCUAMS, INC. Page 27 2005 Collom Vegetation Survey