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Re(crencc Area Selection. <br />• Reference areas Tor each vegetation type were selected based on ecological similarity to the areas to he disturbed. <br />Considerations included dominant and subdominant species, soils, aspect, slope, elevation, past management, <br />water availability, surface ownership by TCC affiliates and lack of future planned disturbance. Final reference <br />area locations are indicated on Map I8, Premising Vegetation. <br />Sampling sites were selected within each reference area in a manner similar to [he procedure described for locating <br />individual sampling points on pre-disturbance sites. Sampling in the reference areas did not occur within hvo <br />meters of the perimeter and neither transec[s nor plots overlapped. <br />Twentymile Coal Company will not establish or maintain a cropland reference area. Anon-reference area <br />standard from Routt Counq~ historical yields will be utilized in evaluating revege[ation success. <br />Samnlinz Methodofoev <br />The procedure for cover measurement consisted of extending aten-meter transect in a random direction along <br />which a ten point optical frame was placed at one meter intervals for a total of 100 points per transect. Percent <br />ground cover was determined by "first hits" on plant species, litter or rack, and bare ground. Transco averages <br />served as one sample (n = I) during sample adequacy calculations and statistical analysis. <br />Current annual productivity was measured by clipping all vegetation within a 0.5 meter by 2.0 meter quadrat (I sq. <br />meter). The quadrat was placed Flat on the ground 90 degrees to the right of the cover transect and at one meter's <br />distance. All current annual production within the quadrat (on a vertical projection) was clipped and bagged <br />• separately by dominant species with sub-dominants grouped by life form. Samples were oven dried at 10~ degrees <br />C for 24 hours and were weighed [o the nearest 0.1 gram. <br />Density of shrubs was determined at each sampling site through a modified point-center-quarter technique. At <br />each sampling point the horizontal plane was divided by the four points of a compass into tour quarters. Within <br />each quarter dte third nearest shrub was identified and the distance from the sample site's center point [o the <br />center of [his shrub was recorded. Sample adequacy was determined using the combined measurements at each <br />sample point as one sample. <br />Calculations for shrub density occurred as follows: each measured distance to a third shrub within a sample point <br />is considered a Yj, where Y is the distance in feet to the identified shrub in the j[h quadrant. To determine the area <br />(ai) sampled at each sample point (i), the following calculation was performed: <br />4 2 <br />ai = (tr/4)(E Y J ) <br />j=1 <br />where: <br />n = 3.14159 <br />2 <br />Y j = The square of the distance (in feet) to the <br />identified shrub in the jth quadrant. <br />Then the density estimate (D~l for each samole point was determined as follows: <br />Di = I I/ai. <br />This density estimate results in a parameter with units of shrubs/square foot and once converted these units are m <br />units of shrubs/acre (from McDonald 1978). <br />MR 97-1~4 2.04-52 Revised i0/02/97 <br />