4 BULLETIN 580, IT. S. DEPARTMENT OF AGRICULTURE. 



period and also the total amount of damage during the entire graz- 

 ing season. An examination was made also at the close of the 1914 

 grazing season. Thus data on seasonal damage are available for two 

 years, and data on total annual damage for three years. 



A supplemental study was undertaken in 1912 to determine the 

 effects of protection from grazing upon the establishment, growth, 

 and recovery of yellow-pine reproduction, and incidentally of forage 

 plants. In each of five areas subject to close grazing and represen- 

 tative of soil classes and forage types in the western yellow-pine 

 belt, 2-aere plots were fenced so as to exclude all grazing. Check 

 plots, established in the immediate vicinity of the fenced plots, were 

 left to the usual amount of grazing. The height and spread of 

 crown of the young trees within the plots were measured, and the 

 location of each tree was recorded. In addition, the severity and 

 probable date of past grazing injuries were noted. These data were 

 secured in 1912, 1913, and 1914. It is planned to repeat the exami- 

 nation every third year until a period of 10 years has elapsed, or 

 until conclusive results are obtained. 



EXTENT OF DAMAGE TO WESTERN YELLOW-PINE REPRODUC- 

 TION FROM GRAZING. 



AVERAGE ANNUAL DAMAGE. 



The average annual damage to western yellow-pine reproduction 

 due to grazing under existing practice is shown in Table I. The 

 figures are those obtained during the final examinations at the 

 close of the grazing seasons of 1912, 1913, and 1914. It will be seen 

 that 42 per cent of the total number of trees observed are damaged 

 to some extent annually. 



Table I. — Annual damage to western yellow-pine reproduction from grazing. 





Number 

 of trees 



ob- 

 served. 







Browsed. 



Year. 





Severely. 



Moderately. 



Lightly. 





Num- 

 ber. 



Per cent 

 of total. 



Num- 

 ber. 



Per cent 

 of total. 



Num- 

 ber. 



Per cent 

 of total. 



Num- 

 ber. 



Per cent 

 of total. 



1912 



8,945 

 8,945 

 8,945 



853 

 492 

 448 



9.5 

 5.5 

 5.0 



1,035 

 871 

 589 



11.6 

 9.7 



6.6 



2,240 



1,301 



698 



25 

 14.5 



7.8 



896 

 915 

 382 



10 



1913 



10.2 



1914 



4.3 









Average annual. . . 



8,945 



598 j - 6. 7 



832 1 9.3 



1.413 | 15.8 



• 731 



8.2 



