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Pikeview Quarry Environmental Assessment Page 36 , <br />i <br />il 1 <br />channel erosion due pr <br />mar <br />y to storm event flows. This process is ongoing and has <br />resulted iri the loss of riparian vegetation as stream banks slough into the channel and aze <br />eroded away. As the stream channel becomes more incised, the level of the groundwater , <br />table in the alluvium is lowered and the water supply for the remaining riparian plant <br />communities is reduced. <br /> ' <br />3.3.3 Vegetation <br />The vegetation composition and community type on National Forest System land ' <br />above the Pikeview Quarry azea is heavily influenced by topography and soil type. The <br />dominant vegetation on the Sphirix-Rock outcrop complex is Ponderosa pine. Typically, <br /> <br />this type of soil also supports Douglas fir and Quaking aspen, and an understory of ' <br />Kinnikinnick, Common juniper, grasses, and fortis. The potential natural vegetation is <br />ponderosa pine. The average annual production of air-dry vegetation ranges from 150 to <br /> <br />300 pounds per acre. Rock outcrops support no vegetation. t <br />The following information was gathered from a site visit to the proposed project azea <br />(July 20001 and a review of literature describing vegetation corrununities found in the Rocky ' <br />Mountain Region (USDA Forest Service 1987a and 1987b). <br />Plant communities located on National Forest System lands west of the quarry azea <br />overlap and can be chazacterized into two distinct but related plant associations (see Table <br />3.7 for a list of plants). The wide diversity of species is due to a combination of factors <br />including it.s location within the transitional zone (ecotone) between grassland and montane ' <br />forest. The resulting variety of vegetation provides habitat that is suitable for many types of <br />wildlife. <br /> , <br />North-facing slopes (upper slopes and board ridges) are inhabited by a more typical <br />Montane (coniferous) forest composed of various mixtures of Ponderosa pine (Pinus <br />ponderosa), Douglas fir (Pseudotsuga menzesii), and Rocky Mountain juniper (Juniperus ' <br />scopulorum). In most forest azeas the Douglas fir is dominant numerically. South-facing <br />slopes (wazm, dry, rocky soils, 55 to 65% slopes, upper and middle slopes) aze composed <br />primazily of a shrub type community of Gambel oak (Quercus gambelli) and Mountain ' <br />mahogany (Cercocarpus montanus). <br />The field survey identified limited invasion ofnon-native species occurring on the ' <br />edge of the quarry or road disturbances and most likely is not located on National Forest <br />land. Visible evidence of fire was found to be wide-spread in the area (estimated 1890-1915 <br />fire activity) and no human disturbances were observed which may have influenced plant ' <br />communities. <br />The plant community was estimated to be in a midseral stage (40-60% of climax), and ' <br />in the shrublands a few species of Pinyon pine and One-seed juniper (in lesser occurrence) <br />and in moister sites White fir (Abies concolor), was noted. <br />Hydrosphere Resource Consultants, 1002 Walnut Street Suite 200, Boulder. CO 80302 ' <br />