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• The beginning of the pipeline route, which lies within the Piceance Site, traverses all five of the upland plant communities described for the Piceance Site, above (see Figure 7-17). Immediately upon exiting the Piceance Site, the pipeline route crosses the cultivated hayfields that occupy the Piceance Creek valley bottom. On the east side of Piceance Creek and Piceance Creek Road, the pipeline route ascends Davis Gulch. The bottom of Davis Gulch is occupied by sagebrush vegetation. As the pipeline route comes up out of Davis Gulch and begins to follow the existing east- west Questar natural gas pipeline corridor, it crosses barren/rock outcrop vegetation that occupies the Thirteenmile Creek Tongue of the Green River Formation at this location. The upland areas from this point to the Greasewood Compressor Station primarily support open pinyon-juniper woodlands. The second pipeline corridor segment includes approximately 11 miles of BLM land paralleling the existing north-south pipeline corridor and extending from the Greasewood Compressor Station south to about 2 miles north of the Rio Blanco County/Garfield County Line (in T4S, R96W, Section 3). Virtually all ridge and upland communities in this segment support pinyon-juniper woodlands (BLM 1998d), for a total of 3 to 4 miles traversed (CIG 1995). This segment also crosses between 5 and 6 miles of sagebrush vegetation and approximately 2 miles of the Mountain Shrub Association (CIG 1995). The Mountain Shrub Association has been described by the BLM as follows (BLM 1994). • Mountain Shrub Association The Mountain Shrub Association is a mixture of large to medium tree-like shrubs, most often Gambel's oak, that have a mixed understory of smaller shrubs, grasses, and forbs. The overstory varies from open to dense stands, and understory species density and diversity are inversely related to overstory closure. In some areas, the mountain shrub type supports the highest herbaceous production and species diversity of any plant association. The association occupies higher elevations on east, west, and north slopes, extending to lower elevations on cool exposures. The primary environmental factor affecting the Mountain Shrub Association is available moisture, as influenced by elevation, soils, topography, and wildfire. It is largely restricted to elevations about 7,000 feet in higher precipitation zones. At lower elevations on deeper, well-drained soils, the type commonly intergrades with the Sagebrush Association. Where it occurs along the proposed pipeline corridor, it occurs primarily on ridgetops and on east- and north-facing slopes (CIG 1995). The third pipeline corridor segment includes approximately 24 miles of private land paralleling the existing north-south pipeline corridor and extending from the southern boundary of the BLM land south to the Parachute Site (in T6S, R96W, Section 34). This segment traverses between 11 and 12 miles of sagebrush • vegetation, 4 to 5 miles of mountain shrub vegetation, including the top of Davis Point (in T5S, R96W, Section 24) (Barrett 1994), and less than 2 miles of pinyon- American soda, L.L.P. '7_3rJ Commerual Mine Plan August 18, 1998