METHOD OF CONSTRUCTION OF THE YIELD TABLE 



425 



TABLE LXIV 

 Trees per Acre Based ox Crown Space 



The above data must now be correlated with age. The steps are 

 as follows: 



1. From a curve of age based on diameter, the diameters at each 

 five-year period are found, and the number of trees per acre, formerly 

 based on diameter, are then interpolated for the fractional diameters 

 corresponding to these exact ages. 



2. From a curve of height growth based on age the height of the 

 average tree is found. 



3. From diameter and height, the volume of each tree is taken 

 from a standard volume table (§ 288). 



4. The yield per acre at each age is the product of the number of 

 trees per acre and this average volume. 



The application of this method is shown in Table LXV, p. 426. 



325. Application of Method to Many-aged Stands. To apply this 

 standard ta):)le to the many-aged forest for the prediction of j'ield, 

 the same principles are used as were described in § 316. But in this 

 case, the number of trees in given diameter classes is the basis of comparison 

 to determine the reduction per cent or density factor. 



It makes no material difference whether the standard table above 

 illustrated exactly represents the true or actually possible normal yield 

 of a pure, even-aged fully stocked stand, provided it approximately 



