RiiviKvvs 705 



Effect of Grazing upon Western Yellow-Pine Reproduction in Cen- 

 tral Idaho. By W. N. Sparhawk. Bulletin 738, U. S. Department of 

 Agriculture. Contribution from the Forest Service. Washington, 

 D. C. 1918. Pp. 31. 



This study was planned in a similar way to the foregoing, namely, 

 by means of sample plots, some 150. on the central Idaho plateau in 

 three locations of the Payette National Forest. The Forest is mixed 

 Douglas fir and lodgepole pine, with some Abies species forming a 

 prominent part of the admixture, the western yellow pine forming on 

 the average in the three locations 40. 58, and 85 per cent of seedlings, 

 respectively. 



"Western yellow-pine and Douglas-fir seeds germinate for the most 

 part during May and the first half of June at the lower and during 

 June and early July at the higher elevations, and occasional seedlings 

 appear all through the summer. Lodgepole-pine germination continues 

 in considerable quantity during most of the season. Western yellow- 

 pine seedlings to a very large extent, and lodgepole pine to a less ex- 

 tent, occur in small, compact bunches, the result of the seeds being 

 buried by chipmunks. . . . 



"Sheep injure forest reproduction directly, both by browsing and by 

 trampling. In the case of browsing the injury may be confined to a 

 few needles or to the tips of side branches, the leader may be bitten ofif, 

 or the bark may be gnawed. With conifers such injuries, except in 

 extreme cases or when repeated, seldom result in permanent deformity 

 or death. . . . 



"If the injury is repeated every year or two, of course the seedling 

 will be permanently stunted and will never become a tree. . . . 



"Very severe browsing, such as frequently occurs on bed grounds 

 which have been used too much, often kills the seedlings outright. 

 . . . To test the efifect of light browsing, only the foliage put out 

 during the current year was removed from a number of other seed- 

 lings. This had no apparent lasting effect, since all were fully recov- 

 ered within a year. . . . 



"Of the three important species present, western yellow pine appears 

 to be most liable to browsing injury, lodgepole pine somewhat less so, 

 and Douglas fir least. White fir is practically never browsed. . . . 



"Of the 1,782 seedlings killed, 1,294, or y^) P^i" cent, were less than 

 a year old, while only 11, or about one-half of i per cent, were over 6 

 inches in height. Only one seedling over 18 inches high was killed by 

 sheep during the three years. Only one sapling over 3.5 feet higli was 



