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MIXED BRUSH TYPE/ASPEN SUBTYPE <br />~. The mixed brush type/aspen subtype vegetation type within the affected <br />area occupies 1762 acres or 83.0% of the total undisturbed lands in the <br />' study area. It is predominant on all slopes and aspects in the study <br />area except for the drier slopes in the southc~stern section of the <br />permit area. It was the frost diverse vegetation type studied with 38 <br />different species encountered in cover quadrats and a species diversity <br />index of 2.72. The type is characterized by the presence of five shrub <br />species, Utah serviceberry, ~miron chokecherry, Gambol oak and Basin <br />big sagebrush distributed in a roughly-clumped fashion throughout <br />continuous stands of irountain snowberry. Aspen stands were intermingled <br />within the type along draws and other areas of high soil moisture at <br />the upper elevations of the study site. For the purpose of evaluating <br />vegetation Dover, frequency, productivity and shrub density, aspen is <br />considered as part of the mixed brush type/aspen subtype. Tree density, <br />age and basal area and shrub height estimates are described separately <br />for aspen. <br />Of the five shrub species, snowberry provided the greatest cover with <br />2.0% basal and 14.9% canopy cover (37% relative shrub canopy cover). <br />It occurred in 45 of the 58 cover quadrats surveyed and was by far the <br />shrub species Trost c~ronly encountered (77.5% frequency). Of the other <br />four shrub species, chokecherry and Gambol oak evidenced the highest <br />basal Dover (0.3%) while Gambol oak shos•r~i the highest canopy cover <br />(7.5%l. Relative to the upland sagebrush vegetation type, total shrub <br />basal cover was lower (2.8% compared to 4.0%} although canopy cover was <br />much higher (39.9% vs 16.9%). <br />Total vegetation basal mover Baas 15.9% and was dominated by the grass <br />and forb strata (7.2 and 5.80, respectively as corrg~ared to 2.8o for <br />shrubs). The most com~ron grass species encountered were Poa pratensis <br />(Kentucky bluegrass), 3.8% cover and 39.7% frequency, and Agropyron <br />trachycaulun (slender wheatgrass), 2.1% cover and 32.8% frequency. <br />Common forb species incl~xied Achillea millefolium (coa¢ron yarrovr), <br />~• 1.2% cover and 31% frequency, Agastache urticifolia (nettleleaf <br />-56- <br />