22 



BULLETIN 738, U. S. DEPARTMENT OF AGRICULTURE. 



Table 13. — Comparative damage from sheep grazing and from other causes. 



i All years and species.) 



Allotment and cause cf injury. 



Dead wood: 



Sheep. . . 



Other.... 

 Silver Creek: 



Sheep. . . 



Other.... 

 South Fork: 



Sheep. . . 



Other.... 



Nature of injury. 



Needles. 



Side 

 branch. 



Leader. 



65 



577 



12 



261 



Bark. 



Tram- 

 pled. 



All not 

 killed. 



194 

 631 



105 

 792 



28 

 290 



Killed. 



753 

 3,022 



970 

 2,797 



59 

 204 



Table 14. — Causes of deaths of seedlings between the end of the summer of 1912 and the 



end of the summer of 191 A- 





Less than 1 year old. 



More than 1 year old. 



Cause of death . 



Western 

 yellow 

 pine. 



Douglas 

 fir. 



Lodge- 

 pole 

 pine. 



Western 

 yellow 

 pine. 



Douglas 

 fir. 



Lodge- 

 pole 

 pine. 



Sheep: 



520 

 838 

 917 

 523 



72 

 119 

 264 



215 



118 

 US 

 523 

 282 

 4 



201 

 201 

 615 

 210 



91 



99 



298 



161 



2 



1 



114 





HO 





267 





125 



Frost : 



1 















166 



2 



240 



7 

 2 

 5 



2 









110 



18 



2 











1 















3 

 2 

 4 

 3 





















7 





















6 

 2 

 2 

 12 











Cattle 







3 



1 

 20 

 5 

 4 

 4 





1 











1 





2 



3 



























3 





2 













1 





1 























Total 



2,719 614 



935 



1,191 



579 



514 



VALUATION OF DAMAGE. 



Using the table of height growth and the average proportions of 

 seedlings of different sizes killed by all agencies on the grazed plots 

 on all areas, curves were constructed to show the per cent of mor- 

 tality at different ages. Table 15 was read off from these curves, 

 and from it was computed Table 16, which shows the number of 

 seedlings of any age up to 20 years necessary to insure a stand of 

 100 trees per acre of any of the three species at an assumed maturity 

 of 150 years. These figures allow for deaths from all ordinary 

 causes, including grazing every year, but, of course, do not allow for 

 extraordinary deal lis due to such causes as fires or epidemics of 

 insects or of fungous diseases. 



