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2. Upland sagebrush - Artemisia tridentata v. tridentata (Basin big <br />sagebrush) dominated comities occurring on well-drained slotaes <br />having soils usually deeper than 15" (Thatcher, 1957) where <br />decreased iroisture conditions limit other vegetation types. <br />3. Aspen - A mixed brush subtype with Popu'lus tremiloides (quaking <br />aspen) stands occurring at the higher elevations generally in <br />proximity to draws where soils are well-developed and soil icnisture <br />wrr3itions are good. <br />The mixed brush type/aspen subtype and upland sagebrush vegetation <br />types on areas that may potentially be disturbed by m;n;nq and ancillary <br />operations (i.e., affected area) were randa~nl.y sampled (as described <br />in detail belaa) to gather production, cover, frequency and shrub <br />height data for the 1979 gracing season. Shrub density data were <br />gathered during the 1980 growing season in an effort to con4ply with <br />proposed Colorado Mined Land Reclamation Board regulations which had not <br />required these data at the time of initial sample design. The aspen <br />subtype com comity was randomly sampled to acquire tree density and <br />dominance (basal area) data. Age data cvere collected for aspen and <br />selected shrub species at several locations throughout the study area. <br />Pdditional shrub height and diameter data were recorded on transects <br />randomly locatEd throughout the mixed brush, upland sagebrush and aspen <br />subtype cormunities. <br />Reference or wntml plots, approximately 5 acres in size, ccere situated <br />in the mixed brush type/aspen subtype and upland sagebrush vegetation <br />types away from areas of potential disturbance. The federal (OSM) <br />and proposed Colorado (CMLRB) Permanent Regulatory Programs and Wyoming <br />DEQ Guideline ~r2 (.`March, 1979) specify that reference areas must be at <br />least 2 acres in size. The reference sites were selected on the basis <br />of containing vegetation species, soils, and topographic aspects <br />generally characteristic of the tcvo ?[ajor vegetation co;mrunities sac~Qled. <br />The reference areas were sampled in a systematic manner to gather <br />comparison vegetative production, cover, frequency and shrub height data <br />~• <br />-4- <br />