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extremes of -45°F and +100°F. Winds are predominantly from the west, but are locally <br />modified by topographic features. The growing season for the area in the vicinity of Craig <br />averages 77 frost-free days. <br />Soil Types <br />Three soil orders are found in the permit area: Aridisols, Entisols, and Mollisols. These soil <br />orders are characteristic of fairly steep, semi-arid regions of northwestern Colorado. They <br />represent soils that grade from recently developed soil bodies with minimum horizon <br />development (Entisols) to older soils with well defined diagnostic horizons (Mollisols). <br />Soil Characteristics and Distribution <br />Overall, the soils found in the proposed permit area are relatively deep and well drained. <br />Effective rooting depth varies from two to sixty inches within the area. The deepest soils <br />yielding the greatest rooting depths occur in valleys and on the leeward sides of ridges. Soil <br />reaction is slightly acid to moderately alkaline over the permit area with the exception of <br />inclusions of small scattered areas with saline substrata. These small areas have probably <br />formed in place from weathered sodic shale. <br />Control of Vegetation Distribution by Climate and Soils <br />Vegetation in the area grows largely in response to macro-climatic influences of the region. The <br />north facing slopes, having moderate to deep soils, a relatively mesic moisture regime, and <br />favorable levels of insolation throughout the year, are characterized by well developed mountain <br />shrub communities. On the colluvial toe slopes, communities dominated by sagebrush and some <br />grasses occur. On the south facing slopes behind the ridgeline of the Williams Fork Mountains, <br />vegetative communities are not as well developed in terms of cover, density, and production due <br />to the less favorable soils, moisture regime, and increased solar insolation. The trend in these <br />areas is toward communities dominated by juniper, pifion, mountain mahogany and xerophytes. <br />Control of Vegetation Distribution by Land Uses <br />Within the permit area, natural vegetative communities have been modified to varying degrees <br />by humans and domestic animals. Much of the land along toe-slopes and valley bottoms has <br />been cleared of native vegetation and is currently used for dry land agriculture. Most of the <br />north-facing slopes in the area have been historically used for the grazing of sheep and/or cattle. <br />The farming and ranching have produced a mosaic of vegetation communities in the permit area. <br />Vegetation Distribution in Permit Area <br />The mountain shrub community in the permit area gradually thins from east to west (in terms of <br />density and cover) and gives way to a community of big sagebrush and grasses on the west end <br />of the mine. Descending northward from the ridge of the Williams Fork Mountains, several <br />changes in community composition are evident. At elevations above 7,200 feet, Gambel's oak <br />dominates the mountain shrub community; serviceberry and chokecherry are less abundant. <br />Snowberry is the most conspicuous under-story component, with an occasional big sagebrush, <br />Trapper Mine 13 September 21, 2009