EFFECT OF GRAZING ON WESTERN- YELLOW PINE. 



17 



As would be expected, the amount of injury and death increased 

 fairly constantly with increased intensity of grazing. Except on 

 bed grounds and areas grazed with similar intensity, the damage was 

 not very serious for seedlings more than a year old, and even in 

 such places only 4 per cent of the seedlings were killed. A con- 

 siderable proportion, from 20 to 30 per cent, of those less than a 

 year old were killed on all except the lightly grazed plots, where 

 only 6.5 per cent were lost. 



Table 8 shows that after their third year a very small proportion 

 of seedlings, less than 1 per cent per year, is killed by grazing of 

 moderate intensity; that is, by grazing close enough to utilize prac- 

 tically all of the palatable forage. 



Table 8. — Seedlings from 3 years old to 1\ feet high hilled by sheep on moderately 



grazed plots. 





Per cent of seedlings on grazed plots 

 killed. 



Allotment and species. 



1912 



1913 



1914 



Average 



for 

 period. 



Deadwood: 







0.7 



.8 



2.5 



0.26 







.5 

 .5 



.47 







1.08 









All 





.3 



1.1 



.51 









Silver Creek: 



Yellow pine 



6.5 







1. 11 



4 r 6 



1.6 





1.07 



White fir 

















All 



5.5 



.8 





.95 







South Fork: 







.8 

 33.3 



















All 







3 













All areas: 









.52 











.98 











1.08 



White fir 





















All 









.76 













Although the plots did not happen to be located so as to show the 

 effect of repeated use of the same bed ground, it was established by 

 observation that the damage on the second and succeeding nights 

 was very much greater in proportion than that on the first night. 

 The first time a bed ground is used the sheep spend the time just 

 before dark and in the morning before they are driven off the area 

 in browsing, first, such forage plants as are present, and then, if 

 they are left too long or forage is scanty, the conifer reproduction. 

 Very few seedlings were browsed on the experimental areas on bed 



