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where: xrev =Average vegetation cover for revegetated area <br />Aa =Aspen type acreage, premining surface area <br />Ab = Mixed brush type acreage, premining surface area <br />As =Sagebrush type acreage, premining surface area <br />A~,~,~„r =Western wheatgrass/alkali sagebrush type acreage, premining surface <br />area <br />xy =Average reference area herbaceous cover -aspen type <br />xb =Average reference area herbaceous cover- mixed brush type <br />xs =Average reference area herbaceous cover -sagebrush type <br />x~,,,w =Average reference area herbaceous cover -western wheatgrass/alkali <br />sagebrush type <br />At =Total of relative community type acreages, premining surface area. <br />For the II-W South Extension Area, the cover standard will be calculated based on the extent of <br />herbaceous cover in five ERA vegeation types. Included in the average will be data from the <br />Aspen Woodland, Mountain Brush, Steep Mountain Brush, Sagebrush/Snowberry, and Western <br />Wheatgrass/Alkali Sagebrush vegetation types. The extent of herbaceous cover in each of <br />these types will be represented by the "all-hit" measure of cover in which the full extent of a <br />species cover, whether overlapped by the canopy of another or not is independently assessed. <br />For an example of this source of cover information, see the cover tables associated with the <br />baseline vegetation sampling reported in Tab 10. Although the development of trunks, <br />branches, twigs, and leaves of shrubs and trees overarches fairly extensive areas in several of <br />the vegeation types, the herbaceous component is still quite extensive in most, though often in <br />the shade of the woody species. For example, in the Aspen Woodland ERA of the II-W South <br />Extension Area, herbaceous cover based on all-hit data is 90.1 percent. An average of the <br />herbaceous cover of the ERA types, weighted by their extent in the permining area, would be <br />calculated using the formula stated above for the II-W area, but using "all-hit" data rather than <br />"first hit" data as was done there. <br />xrev ~ 0.90 IIAaI Ixal + IAbllxbl + IASbI (xsbl + IAsllxsl + (Aww) (xwwll <br />At <br />where the symbols are used as specified above and <br />Aso= Steep Mountain Brush type acreage, premining surface <br />Xso= Average reference area herbaceous cover -steep mountain brush type <br />For example, based on the sampling of the II-W South Extension Area during the baseline year, <br />the following data would be used: <br />40 Revised 1/99 <br />