STUDIES IN ARIZONA AND NEW MEXICO 



203 



Stand was recorded during the first few weeks of each growing 

 period, that is, before June 15. The greatest damage, on the 

 other hand, occurred during the latter half of June and early in 

 July. However, considerable damage was noted throughout the 

 entire grazing season 

 and in the autumn 

 when the forage be- 

 came dry and some- 

 what unpalatable. 



Injury in Relation 

 to Intensity of Graz- 

 ing and Character and 

 A hundance of Forage. 

 — Sheep were found 

 to be considerably 

 more destructive to 

 young timber repro- 

 duction than were 

 cattle and horses. 

 On overgrazed areas, 

 however, all classes 

 of stock are liable to 

 cause more or less 

 serious damage to re- 

 production. Under 

 such conditions cat- 

 tle and horses may injure as much as 10 per cent of all tree 

 growth less than 5I feet in height (Fig. 67). Under normal graz- 

 ing, that is, grazing that is not destructive of the forage crop, 

 sheep may injure as much as 11 per cent of the reproduction 

 under 5^ feet in height. The sheep range studied was about 

 average for the type, and the stock were well adapted both to 

 the character of the forage and to the topographic features. 

 The way in which the stock is handled has much to do with the 

 severity of the grazing injury. Where cattle were permitted to 

 congregate, as much as 22 per cent of the total tree stand be- 

 tween 3 and 6 feet in height was injured in varying degrees 



Fig. 66. — yellow PINE 5 FEET TALL INJURED 



BY CATTLE BROWSING AND RUBBING. 



Injury to the terminal shoot by the browsing of cattle seldom 



occurs after the saplini; attains a height of s' feet. 



