344 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 30 



grass is destroyed and the pasture becomes capable of sustaining 

 only a very limited number o,f livestock. This condition has be- 

 come extensive at one time or another throughout the western 

 United States where stock has been ranged. The situation is 



1C>12 191^ Hl» WIS 191g 1917 1918 1919 1920 1921 1922 X92-; 19 2» 1926 1 986 1927 



: R 



i 



AVERAOI ViauE~ 



PiGUKB 12.— Number, average value, and total value of lynx skins produced in 

 Alaska from 1912 to 1927, inclusive 



graphically shown by the illustration of the extermination of a 

 species, wherein the range or vegetation is represented by the area 

 labeled basic stock and the carrying capacity or annual forage pro- 

 duction is represented by the area marked "Annual surplus." It 

 can also be illustrated by the following diagram (fig. 13). 



