3262 



Chapter 27 



I 



50 100 150 200 250 300 

 NUMBER OF TREES PER ACRE 



Figure 27-3. — For certain combinations of age and site index, board-foot yields (Inter- 

 national y4-inch rule) of yellow-poplar culminate with increasing stand density. These 

 even-aged, unthinned stands were in the Appalachian Mountains of North Carolina, 

 Virginia, and Georgia. Site index, height at age 50, is 100 feet. (Drawing after Beck 

 and Della-Bianca 1970, p. 4.) 



by multiplying log length by cross-sectional area. The principal variation among 

 cubic foot scales is in the method of computing cross-sectional areas of logs and 

 trees. 



The most common cubic log rule is Smalian's formula: 



V = 0.005454 [ 



D2 



]L 



(27-12) 



