396 JOURNAL OF FORESTRY 



ative and pretends to no degree of accuracy. The most striking thing 

 brought out is the hghtness of the sprout reproduction in comparison 

 with the clear-cut plots, where 20,000 to 30,000 per acre is about the 

 average. 



Effect of Live Stock and Other Influences on Reproduction 



While it has been shown that sprouts are produced in much greater 

 numbers following clear cutting than is necessary for the production 

 of a maximum timber stand, provided, of course, that the majority 

 of the sprouts are established, grazing and occasionally rodents may 

 under certain conditions practically eliminate the young sprouts. The 

 handling of live stock in the aspen type on'^National Forests is a rather 

 general practice, and for this reason the question of the relation of 

 grazing to the establishment of the aspen stand was deemed worthy of 

 careful study. 



Effect of Broivsing by Cattle and Sheep 



Observations extending over a five-year period (1912 to 1916, in- 

 clusive) on range in the aspen type used by sheep and cattle separately 

 showed the following results : 



(i) Sheep are responsible for severe damage to the reproduction 

 regardless of variety and abundance of forage, and the injury to and 

 mortality of the sprouts was found to be roughly proportional to the 

 closeness to which the lands are grazed. Even where the cropping by 

 sheep was light, the damage was severe. 



(2) As a rule, three years of successive moderate grazing by sheep 

 on clear-cut lands resulted in the destruction of the entire sprout stand. 

 Even in the autumn, after the leaves had dropped, sheep devoured a 

 considerable portion of the stems of the season's growth, regardless 

 of the presence of abundant palatable herbaceous forage. 



(3) Cattle devoured the leafage and young twigs and branches of 

 aspen reproduction to a slight extent, but the injury was never severe 

 except where the lands were overstocked or where the animals were in- 

 clined to congregate and remain for a considerable period. Where 

 cattle grazing was moderate and the stock properly distributed, how- 

 ever, the reproduction was never browsed to the extent of endangering 

 the establishment of a full commercial stand. 



Because of the difference in destructiveness to reproduction by cattle 

 and by sheep, the study points to the fact that where considerable areas 

 are to be clear-cut the range may be grazed moderately by cattle during 



