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• Sampie adequacy requirements for affected area cover data were <br /> calculated using the OSM formula <br /> s2t2 <br /> nmin. (d-)2 <br /> where nmin = the minimum adequate number of cover transects <br /> s2 = sample variance <br /> t2 = a designated t-statistic (0.84 for a one-tailed test <br /> with 80% confidence) <br /> d = desired limits of detection (0.1, or 1G07o) <br /> x = sample mean <br /> 2.2.3 Collection and Analysis of Production Data <br /> Production data were collected in 1980 by clipping current year's <br /> growth of all herbaceous plants. Species except minor forbs were <br /> sorted and bagged separately in the field; minor forbs were bagged separately. <br /> Each production plot yielded one composite sample. Domestic livestock were <br /> not present in the study area until after the sampling period, so fenced <br /> exclosures were not necessary. <br /> • In the laboratory, clippings were oven-dried at 1050C for 24 hours <br /> and weighed to the nearest tenth of a gram. Data were recorded as grams per <br /> square meter (g/m2) .. Statistical adequacy requirements for production were <br /> calculated usina the OSM formula above, except that mean production was used <br /> in place of mean cover. <br /> 2.2.4 Collection and Analysis of Shrub and Tree Data <br /> Measurements of shrub height and density were taken along each <br /> cover transect. Heights were measured to the nearest centimeter for all <br /> individual shrubs intercepting the 50 m transect line. Densities were obtained <br /> by counting all shrubs within 8 m2 circular plots centered on the end of the <br /> transect line. <br /> Tree densities within stands of mature Quaking aspen wpuL_4 <br /> tzemuCv.LdeA were obtained using a point-centered quarter method (Mueiler- <br /> Dombois and Ellenberg 1974) . At the end of each cover transect , the distance <br /> was measured to the center of the nearest tree in each of four quadrants; <br /> heiaht and diameter were also measured for each sampled tree. Density, <br /> height , and diameter data were recorded by species. <br /> Tree densities in open conifer parkland stands were estimated <br /> using a different method better suited for the clumped distribution typical <br /> of these areas. The method consisted of counting all trees within 50 m by <br /> . 30 m quadrats oriented along the contour of the slope. Quadrats were randomly <br /> located within areas selected for their proximity to existing affected areas. <br /> Diameter at breast heiaht was also reccrded. for a.li trees within tlhe quadrats. <br /> -4- <br />