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student's t test one of the denominators, rij, in the square root should be changed to n;. 78. Seneca Coal Company responded to the Division's concerns of density of concentrated shrub azeas by increasing the number of concentrated shrub azeas and increasing the number of acres to be occupied by the concentrated shrub areas. The proposed number of concentrated shrub areas has been increased from eight to fifteen, and twenty acres to twenty-nine acres. Seneca Coal Company has proposed locating the shrub concentration azeas to establish travel corridors and breaking up large extents of grassland dominated reclaimed areas, thus providing greater "edge" for wildlife usage. This increase in concentrated shrub areas is an increase from 5% to 7% of the first permit term disturbance area. Seneca continues to propose a woody stem density standazd of 250 stems per acre throughout the reclaimed area, with 1000 stems per acre standard applied to the concentrated shrub areas. The Division commends"the proposed increased number of concentrated shrub areas, spatial diversity, and increased acreage occupied by the concentrated shrub areas, but the Division continues to question the overall proposed shrub density. Seneca Coal Company contends that the Division is requiring "restoration of moderate to high densities" of woody plant species. Review of the pre-mine vegetation inventory indicates that the mine site is dominated by woody plant species. Aspen, mountain brush and sagebmsh communities account for 79% of the vegetative communities existing within the projected disturbance area (PAP Tab 10 Table 1). Referring to Seneca Coal Company's submitted baseline data, the Aspen community had 7039 stems per acre, Mountain Brush community contained 12,562 stems per acre, and the sagebrush community had 6087 stems per acre. Without calculating acreage weighted values, it is clear that Seneca Coal Company's proposal of 250 stems per acre on the reclaimed areas accounts for 4% or less of the pre-mine community stem densities. The Division's concern that a 96% reduction in woody stem density over a 404 acre area hardly constitutes a request for "restoration of moderate to high density". Once again the Division questions if 1000 stems per acre within the concentrated shrub azeas constitutes an adequate density for utilization by wildlife. Concentrated shrub areas are thought to be utilized by wildlife for thermal and hiding cover. A study conducted in 1981 at the Trapper Mine, ("Reestablishment of Shrubs at the Trapper Mine" by H. B. Humphries, W. E. Sowards, and L. W. Henderson), near Craig, Colorado indicates that concentrated shrub areas should provide hiding cover suitable to camouflage large animals, mule deer or elk, once it is 50 feet into the concentrated area. This study determined that a concentration of 2352 stems per acre were needed to achieve adequate hiding density in the mountain brush community near Craig, Colorado.