976 



A NATIONAL PLAN FOR AMERICAN FORESTRY 



in Pennsylvania. Not enough of such forests is left to be of any 

 immediate importance from the standpoint of management. The 



EXISTING GROWING STOCK-OAK 



EXISTING GROWING STOCK OTHER HARDWOODS 



PROBABLE AVERAGE GROWING STOCK, I F WORKED 

 ON SELECTION BASIS OVER CONSIDERABLE AREAS 



SMALL MEDIUM 

 TIMBER TIMBER 



6 8 10 IZ 14 16 18 20 2Z 24 a& 28 30 32 34 36 38 40 42 44 46 48 50 K 54 56 58 60 SMALL MEDIUM LARGE 



DIAMETER BREAST HIGH (INCHES) v v- ' 



TIMBER GROUP TOTALS 



FIGURE 22. Distribution of cubic volume by diameter classes on average acre, well-stocked oak-hardwood 

 forest, from H-acre plot, Mont Alto State Forest, Pa. Very few stands in the region outside the State 

 forest have such excellent stocking. 



stand is of interest, however, as showing that the virgin forests of the 

 region formerly contained a very heavy growing stock. Good man- 



VOLUME 

 CU.FT. 



3,000 

 1,800 

 1.600 



EXISTING GROWING STOCK -WHITE PINE 

 EXISTING GROWING STOCK - HARDWOODS 

 EXISTING GROWING STOCK - EASTERN HEMLOCK 



SMALL 

 TIMBER 



6 8 10 \Z 14 16 18 ZO Zi Z4 Z6 28 30 33 34 36 38 40 UZ 44 46 48 50 5Z 54 56 58 60 SMALL MEDIUM LARGE 

 DIAMETER BREAST HIGH (INCHES)' V.MBER GROUP TOTALs' 



FIGURE 23. Distribution of cubic volume by diameter classes on average acre, virgin white pine, 



Pennsylvania. 



agement necessitates building up stands toward that condition, but. 

 of course, not to the full degree shown by the virgin forests, 



