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 test a 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 : 



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. 



a Made by L. Margolin for the Forest Service in cooperation with the State of 

 New Hampshire. 



