THE YIELD OF A FOREST. 



17 



standing to mature. That time is found by studying 

 the rate of growth in diameter. 



This method of determining the ^deld by area is much 

 the most practicable of the three for the forests of the 

 United States, and in general it is the simplest and 

 most widel}^ useful of all, because it does awa}^ with the 



Fig. 9.— a forest from which more than the yield is being taken. Big Trees in 

 the Sierra Nevada Mountains, California. 



difficult task of determining the j^early increase in 

 wood. 



The objects in handling forests are so various that 

 sometimes no single one of these methods is satisfac- 

 tory, and then combinations of them are of great use. 



