222 



FRUSTUM FORM FACTORS 



whose volume is sought. If frustums having a fixed top diameter 

 limit are used, the form factors should have been computed from trees 

 measured to this same top diameter. If on the other hand, an attempt 

 is made to base the table on variable or actual used top diameters, then 

 the average actual top diameter for each diameter and height class 

 should first be found and the frustum having the requisite top dimen- 

 sion for each class computed. 



TABLE XXXV 



True Frustum Form Factors for Longleaf Pine, from Frustums Whose Top 

 Diameters Coincide Exactly with the Average Top Diameter of Trees 

 of Each D.B.H. and Height Class 



Merchantable Length in 16-foot Logs 



It is possible, of course, to prepare a table of frustum volumes using 

 fixed top diameters, and compute the form factors of trees for those 

 classes whose top diameters are larger or smaller, but in this case the^ 



