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4 - 56 <br />4.5.6 MEASUREMENTS <br />4.5.6.1 COLLECTION AND ANALYSIS OF COVER DATA <br />Cover was estimated using apoint -intercept method along randomly located and oriented <br />transects (Mueller - Dombois and Ellenberg 1974). Twenty points were sampled along the 50 <br />meter length transects. Paired points were sampled at each 5 meter interval of the transect. <br />Each paired point was 0.75 meter from the transect and perpendicular to the transect. <br />The citing device was mounted on an adjustable tripod to facilitate vertical or orientation and <br />point stablilization. Fine cross hairs were used in the citing device to provide optimum point <br />definition. At each sample point, the citing device was first directed vertically upward, then <br />vertically downward. It a tree and/or shrub was intercepted a second or third hit was taken. <br />The first hit along a vertical line was recorded as vegetation (by species), rock, litter, or soil. <br />Vegetation intercepted below tree and shrub first hits was recorded as a second or third hit. <br />Only first hits were used in calculating percent cover. <br />Sample adequacy requirements for affected area cover data were calculated using the OSM <br />formula <br />• = S2 TZ <br />N min (d X )2 <br />where nm~~ =the minimum adequate number of cover transects <br />s2 =sample variance <br />tz = a designated t -statistic (0.84 for aone -tailed test with 80% confidence) <br />d =desired limits of detection (0.1 or 10%) <br />x =sample mean <br />4.5.6.2 COLLECTION AND ANALYSIS OF SHRUB AND TREE DATA <br />Shrub heights and densities and tree heights, densities, and diameters ant breast height <br />(DBH) were measured at each cover transect location. In some vegetation types additional <br />sample sites were randomly located to meet sample requirements. <br />• <br />M~ Volume 1 4-29-96 <br />