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Acreages of each mapping unit were determined by standard polar planimeter <br />techniques applied to the final topographic base map. To ensure accurate <br />acreage determinatiwi, each mapping unit was measured twice (or more if <br />measurements varied by more than 5~) and the average used to compute <br />.. acreages. <br />VEC,'ETATION PFmDUCPION, COVER, FRE4i7ED7CY AND SHE2UB HEIQiTS <br />Sample Site Location. Areas to be affected by mining activities were <br />delineated on aerial photographs (1" = 400'). A random method was used <br />to locate all affected area vegetative production, basal cover, frequency <br />and shrub height sailing points. This method entailed overlaying a <br />grid system on the aerial photograph displaying the affected areas. A <br />random numbers table was then used to detP.*n~ne grid coordinates (spaced <br />at 1.97 czn intervals) and thus sampling points. The grid crn~letely <br />overlaid the entire study area. <br />Each point randomly located by this technique on the aerial photograph <br />was transferred to a topographic base map and then located in the field <br />by pacing from recogiv.zable landmarks. All randomly located sample <br />points were marked with a wooden stake which identified the sample <br />number and vegetation type. All points were flagged above the vegetation <br />to allva easy relocation. One cover quadrat and one production exclosure <br />were situated at each random point. Cover quadrats were placed in a <br />consistent manner with one corner touching the south side of the sample <br />location stake. Production exclosures were situated 5 m north of each <br />sample location stake. This technique ensured the unbiased positioning <br />of both cover quadrats and production exclosures around the randomly <br />located sample point. <br />Mixed brush type/aspen subtype and upland sagebrush control areas were <br />systematically sampled to obtain production and cover data. Because <br />aspen is a subtype of the mixed brush vegetation type and for most <br />vegetative parameters was sampled with the mixed brush type (understory <br />vas similar to that of adjacent mixed brush areas), no reference areas <br />~. are needed for the aspen subtype. Production exclosure cages and cover <br />-6- <br />