2018-01-03_PERMIT FILE - C1981010A (12)

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of the plant cover over vast areas of the semiarid lands of the West, ranging in altitude from about 3,000 feet in Oregon and 3,300 feet in Montana to timberline in the mountains of Colorado. However, it grows most abundantly on the valley bottoms, plains, foothills, and mesas up to about 8,000 feet, occupying much of the semidesert lands throughout the Intermountain region and northward through Wyoming, Idaho, eastern Oregon, and eastern Washington. It usually appears in open stands, frequently covering great expanses of country with a dense gray man- tle, which is often referred to in ecological literature as the "Northern Desert Shrub Formation." Because of continued overgrazing, with the resultant death or decimation of the valuable perennial bunchgrasses, vast areas of western range contain almost pure stands of this species. Big sagebrush grows on a variety of soils, from the shallow rocky loams of foot- hills and slopes to the vast areas of disintegrated lava formations in the Snake River plains of Idaho and eastern Oregon, but seldom occurs abundantly on soils of granitic origin. In northern Nevada and Utah it principally inhabits the rich • limestone soils of the valleys and foothills. This species grows most typically and luxuriantly with wheatgrasses, bluegrasses, rabbitbrushes, and snakeweed on the deep, well -drained alluvial clay loams at the foot of the main mountain slopes. In the open ponderosa pine, oak brush and pinon-juniper belts it ordi- narily appears in association with wheatgrasses, snowberries, lanceleaf yellow - brush, serviceberries, and needlegrasses. This plant thrives best on rather light, pervious, well -drained, alkali -free soils having a good water supply, as its deep roots facilitate utilization of water that percolates to considerable depths. Big sagebrush is frequently killed by flooding or by the rise of the water table above the subsoil horizon. Tall, dense stands of the plant are indi- cative of fertile soil suitable for small grains and adapted for irrigated farm- ing. Despite low palatability, this shrub is important to western stockmen, due to'its wide distribution and abundance over enormous areas of easily accessible range. On the summer ranges or where succulent forage is plentiful big sagebrush is un- important and even ranks as a pest in many places. Where abundant this species • often furnishes considerable feed for sheep and goats on the lower ranges, parti- cularly those used for winter grazing. Generally speaking, cattle browse the 2-88