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--. -~ C~ Memo to Erica Crosby -3- May 25, 1995 Yoast Mine, File No. C-94-082 mine vegetation inventory indicates that the mine site is dominated by woody plant species. Aspen, mountain brush and sagebrush 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 areas 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. . Comparison with other surface coal mine permits in northwest Colorado indicate higher overall woody stem density standards than 250 stems per acre. Woody stem density monitoring data from 1994 indicates that on sites that have had 5 growing seasons, live shrub densities of 300 per acre are achievable. Again the Division does not consider that reestablishment of somewhat higher than 2-4% of the pre-mine woody stem densities is undue in an region that is dominated by woody plant communities. The Division requests that Seneca Coal Company propose either a higher overall woody plant density success standard or propose a higher density within the concentrated shrub areas. Based on woody plant cover density recommendations found in the Humphries, Sowards, and Henderson paper referenced previously, the Division suggests a woody plant density standard of 450 stems per acre overall with concentrated shrub areas at 2300 stems per acre.