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Reference Area Selection. <br />• Reference areas for each vegetation type were selected based on ecological similarity to the areas to be 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 18, Premining Vegetation. <br />Sampling sites were selected within each reference area in a manner similar to the procedure described for locating <br />individual sampling points on pre -disturbance sites. Sampling in the reference areas did not occur within two <br />meters of the perimeter and neither transects nor plots overlapped. <br />Twentyinde Coal Company will not establish or maintain a cropland reference area. A non -reference area <br />standard from ROUII County historical yields will be utilized in evaluating revegetation success. <br />Samplinz Methodoloev <br />The procedure for cover measurement consisted of extending a ten -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 rock, and bare ground. Transcct averages <br />served as one sample (n = 1) 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 105 degrees <br />C for 24 hours and were weighed to 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 tfte third nearest shrub was identified and the distance from the sample site's center point to the <br />center of this 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 jth quadrant. To determine the area <br />(ai) sampled at each sample point (i), the following calculation was performed: <br />where: <br />4 2 <br />ai = (7r/4)(E Y j ) <br />j=1 <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 santole 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 in <br />units of shrubs/acre (from McDonald 1978). <br />MR 97-154 2.04-52 Revised 10/02/97 <br />