170 FIRST BOOK OF FORESTRY 



it has been found as a matter of experience and measure- 

 ment that the volume of the trunk of the tree is about 

 one half as much as the volume of the cylinder just men- 

 tioned. Usually this ratio between the cylinder and the 

 real volume of the tree varies from about 0.45 to 0.60 

 according to the kind of tree, and naturally is larger 

 if the entire tree, limbs and all, is taken than if only the 

 volume of the stem is to be calculated. This figure, or 

 ratio, is called the factor of shape and is very useful in tree 

 measurement. 



Since the factor of shape is equal to the volume of the 

 tree divided by that of the cylinder, or since 



„ _ volume of tree 



volume of cylinder 

 we can say : 



factor X volume of cylinder = volume of tree ; 

 or, volume = area x height x factor of shape. 



In our case, then, 



3.14 x 90 X .00= 169.5 cubic feet. 



This includes the logs as well as limbs, and means that 

 if the entire tree were cut into cord w^ood, it would make 

 one hundred and sixty-nine cubic feet, solid wood ; or, 

 since about ninety culnc feet solid make one cord of wood 

 in the pile (air and wood), each twenty-four-inch tree 

 would make 1.88 cords. Allowing two cords of wood to 

 each thousand feet B.M. of logs, we deduct one cord for 



