36 CIRCULAR 925, U. S. DEPARTMENT OF AGRICULTURE 
F—468701 
FiGuRE 17.—By 1947, after 13 years of moderate grazing, black sagebrush was the 
dominant species on moderately grazed range (left). Vegetation on heavily grazed 
range (right) was still characterized chiefly by small rabbitbrush. 
species increased and that of the undesirable small rabbitbrush declined. 
The greatest recovery was made by black sagebrush. In 1934, yield 
of this highly palatable species was 21 pounds per acre, only 7 percent 
of the total herbage. By 19388 its production had more than doubled, 
largely as a result of increased vigor of the existing plants. In 1947 
it produced 296 pounds per acre, almost 15 times as much as in 1934. 
A large part of the increased yield during this latter period came from 
the establishment and growth of a large number of seedlings. Through 
this recovery and improvement black sagebrush became the most 
important forage species, producing about 438 percent of the herbage 
and 48 percent of the forage. In contrast, black sagebrush remained a 
minor species on the heavily grazed range. 
Yield of winterfat, the most productive species in 1934, doubled by 
1938 under moderate grazing. Thereafter this species declined as black 
sagebrush increased. But, in spite of the decrease, the yield of winter- 
fat in 1947 was about 50 percent greater than in 1934. On the adjacent 
heavily grazed range winterfat decreased about 15 percent below the 
1934 yield. 
Small rabbitbrush, an undesirable species which often invades heavily 
grazed ranges, increased moderately up to 1938 and then decreased 
drastically on the moderately grazed range. Under heavy grazing it 
increased steadily and the yield in 1947 was 268 percent greater than in 
1934. On the heavily grazed range it produced nearly one-half of the 
total herbage in 1947. : 
