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CIRCULAR 870, U. S. DEPARTMENT OF AGRICULTURE 



3. Open, rolling slope. — These sites, with a gradient of 10 to 25 

 percent, have an open cover of trees and shrubs and only scattered rock 

 outcrops (fig. 10). Most of the sandy loams are about 24 inches deep. 



4. Rocky brushy, rolling slope. — The average gradient of these sites 

 is greater than for the open, rolling slope but the range in gradient, 10 

 to 25 percent, is about the same. In general, the soils are shallower and 

 coarser and more of the surface is covered by rocks, shrubs, and trees 

 (fig. 11). Such lands comprise more acreage than any other site class 

 within the area of granitic soils. 



5. Rocky brushy, steep slope. — These sites have a gradient of 25 per- 

 cent or greater and numerous rock outcrops or many shrubs and trees. 

 The steep areas are not common in the lower foothills; they differ con- 

 siderably from place to place, including some productive soils as well as 

 thin, sandy soils. 



6. Steep, rocky bluffs. — These localized areas are small in size and 

 practically unused by cattle. 



Figure 11. — Slope with common occurrence of trees, shrubs, or rock outcrops. Graz- 

 ing capacity for most of this kind of range land with rolling-to-steep slopes is from 

 2 to 3 acres per animal-unit month. 



The relative herbage production of each site class was estimated from 

 yield measurements made in pastures 1, 2, and 3 during the period 1943-45 

 (table 4). The yield from the best site was almost nine times that from 

 the poorest, and the differences between sites are evidence that the grazing 

 capacity of foothill ranges is related more closely to the sites than to the 

 total acreage of the range unit. Steep slopes were not well represented 

 within the sampling areas, but though not precise the yields estimated for 

 the steep-slope site class are considered indicative of average production 

 on such sites. The differences in yield between north and south exposures 

 were determined from observations extending over 10 years. On north 



