970 



A NATIONAL PLAN FOR AMERICAN FORESTRY 



FIGTJRK 18. Distribution of cubic volume by diameter classes on average acre, northern hardwood second- 

 growth stands, with some timber left from previous stands. A, Stand in White Mountains. Thinnings 

 from inferior species among the small timber would remove surplus from that group and hasten growth 

 of released trees into larger groups; B, represents average of considerable areas in Pennsylvania. Distri- 

 bution of size classes is better, but larger classes need building up. 



TABLE 23. Number of trees, volume, and growth in all-aged northern hardwood 

 stand in northern White Mountains, New Hampshire 



