GRAZING RANGES IN SOUTHERN ARIZONA. on 
Recovery.—lIt is the unanimous opinion of all who know the region 
that the carrying capacity of the completely protected area has im- 
proved very much over its condition at the beginning of the experi- 
ments. There is hikewise no doubt that the carrying capacity of the 
inclosed areas under stock is now greater than that of the adjacent 
unfenced land of similar character. 
fate of recovery.—Previous publications relative to this project 
have stated that recovery of that part of the reserve inside the large 
field and lying above the 3,500-foot contour occurred in marked 
degree in about three years after inclosure. The improvement in that 
area since that time has centinued, but the increase in productivity 
has been growing less and less each year, indicating that that part of 
the reserve has now about completely recovered. The area of in- 
creased productivity has been gradually spreading until all parts of 
the inclosure are now more or less improved. In the opinion of the 
present writer, that part of the reserve below the 3,200-foot contour 
may be expected to continue to improve for a number of years more, 
under protection, and the recovery experiment should be continued 
at least until such time as complete recovery of this area is obtained. 
Some definite answers are now available as to the time necessary 
for recovery under different conditions. Three years of complete 
protection gave about three-fourths of complete recovery for the area 
where crowfoot grama is the dominant grass, at levels of about 3,500 
to 4,000-feet, where an annual rainfall of 15 to 18 inches occurs. One 
inclosed pasture of this type having an area of 794 acres, which has 
been stocked with horses and burros at the average rate of about 11 
head per section, recovered somewhat more slowly than the com- 
pletely protected area beside it and at the same level, but after 11 
years protection is now not appreciably different in carrying capacity 
from the completely protected area, a condition which has obtained 
on this pasture for the last two or three years. This would indicate 
that this pasture recovered under light stocking in about double the 
time required for the completely protected area. Areas at higher 
levels might be expected to do at least as well if not better under 
similar treatment. 
Three other areas, 1,065, 1,695, and 1,889 acres in extent, respec- 
tively, which have been judiciously pastured with approximately 
all the cattle they could carry, are known to show better productivity 
than adjacent unprotected grazing land of the same character; 
and by their users these areas are believed to have materially 
increased in carrying capacity under this kind of treatment within 
a period of 11 years. Table VII and the curves in figure 5 show a 
gradual increase in numbers carried on the two larger areas. Hence, 
if these pastures have been stocked to their proper limit all the time 
and the condition of the pastures has not declined, the curves indi- 
