94 



THE woodsman's HANDBOOK. 

 Growth — Board Foot Volume. 



Table 8 gives an idea of the growth per cent in entire tree vol- 

 ume. For trees up to 4 or 5 inches in diameter the board-foot 

 volume is, of course, zero, and few log rules give board-foot con- 

 tents for log diameters below 6 inches, which means a tree 7 or 8 

 inches in diameter (at 4.5 feet from the ground). For small trees 

 the board-foot content shows only about 4 board feet per cubic foot 

 of log; this rises to 8 board feet per cubic foot in large trees. The 

 proportion of waste in bark, top, and stump is also smaller in large 

 trees. For these reasons the board-foot volume growth has an extra 

 increase which requires increasing the per cent given in Table 8. 

 A mill testa in white pine, sawing round-edged box boards, showed 

 the following relation between total cubic-foot volume increment 

 and board-foot increment for trees of different diameters with aver- 

 age height growth : 





Relation of board foot 



Diameter of 



(box-board sawcut) in- 



tree. 



crement to total vol- 





ume increment. 



Inches. 



Times. 



6 



1.4 



8 



1.2 



12 



1.2 



18 



1.1 



24 



1.0 



So that if the volume growth of a tree in round-edged box boards 

 is desired, the growth per cent in the table on page 93 should be 

 increased 1.4 times for 6-inch trees, 1.2 times for 8 to 12 inch trees, 

 and 1.1 times for 18-inch trees, while for 24-inch trees the board- 

 foot growth per cent equals the total volume growth per cent. 



o Made by L. Margolin for the Forest Service in cooperation with the State ol 

 New Hampshire. 



