THE YIELD OF A FOREST. 



15 



for a number of years, should be cut from the forest 

 in the corresponding- period. Thus, if the growth or 

 increase is 100 cords a year, that amount might be har- 

 vested yearly b}" cutting eyery tree on a small area, by 

 cutting fewer trees per acre on a larger area, by dis- 

 tributing the cut eyer\^ 3'ear oyer the whole surface of 



Fig. 8.— Measuring an average tree. Adirondack Mountains, New York. 



the forest, or by cutting 1,000 cords in an}" one of 

 these w'djs once in ten years. 



There are many different methods of finding what 

 is the annual increase of wood in a forest. One ol: 

 the simplest is to count the number of trees upon an 

 acre and select an average tree, then to cut it down, 

 measure its cubic contents, and hnd its age b}^ count- 

 ing the annual rings. That done, the 3^early increase 



