EFFECT OF GRAZING ON WESTERN YELLOW PINE. 13 



grasses occur in much purer stand than over the remainder. In the 

 rest of the Forest blue grama, Gambel's oak, and succulent weeds 

 form a considerable percentage of the vegetation comprising the 

 bunchgrass type. Extensive observations in this portion, supple- 

 mented by many others in the yellow-pine type in the Southwest, 

 bear out the conclusion that where sheep are not forced to depend 

 upon the rank growth of bunchgrasses for the main part of their 

 feed, but have access to plenty of browse and palatable weeds, they 

 will not cause such severe damage to yellow-pine reproduction in the 

 bunchgrass type. If, however, the browse and weeds are not suf- 

 ficient to supply the bulk of their feed, they are likely to cause very 

 severe injury to young pines. 



The portion of the bunchgrass type on the Coconino Forest, over 

 which the damage is excessive, includes about one-third of the total, 

 or 130,000 acres. A circumstance which makes the injury to repro- 

 duction here a serious matter is the fact that where the worst damage 

 occurs reproduction is scattered, and for that reason is in special need 

 of protection. 



CLASS OF STOCK AND METHODS OF HANDLING. 



CLASS OF STOCK. 



It is comparatively easy to determine the amount of damage for 

 which cattle, horses, and burros are each responsible, because fre- 

 quently these classes of stock are handled in pastures where each may 

 be observed separately. In the case of sheep, however, which are not 

 handled in pastures on the Coconino Forest, but share the open range 

 with other classes of stock, it is difficult to determine the proportion 

 of the damage with which they can properly be charged. To arrive 

 at a conclusion it was necessary to compare the amount of damage 

 found on range occupied by both cattle and sheep with the amount 

 of damage under similar grazing conditions on areas from which 

 sheep are excluded and in pastures. This measure of sheep damage is 

 believed to be fairly accurate, since there is no evidence that cattle 

 do more damage to reproduction on a range which they share with 

 sheep than on a range which they graze alone. Sheep injuries, 

 furthermore, are characteristic and may be readily distinguished 

 from those of cattle and horses. 



It is believed that horses and burros may be eliminated from the 

 classes of stock responsible for severe injuries to reproduction. The 

 many saddle horses, in all kinds of physical condition, ridden in the 

 yellow-pine type, have shown no disposition to eat coniferous repro- 

 duction. In a pasture 4 miles southwest of Flagstaff about 30 head 



