28 



PRELIMINARY CALCULATIONS 



Illustration 3. — To Compute Contents of Standing Trees in Cubic Feet or 

 Cords. 



Explanation. — The object of this illustration is to demonstrate a method of 

 determining the volume of standing trees in cubic feet or in cords. The 

 Schiffel formula (see Problem 13, Illustration 2) may be used for computing 

 the volumes in cubic feet and the contents in cords may be determined by 

 dividing the total cubic volume by 90. This converting factor of 90> is based 

 upon the supposition that a cord of wood contains 70 per cent solid wood. 

 This of course will vary with the method of piling, and the size and form of 

 the pieces. Should the trees be crooked or knotty, and the wood be split in 

 small pieces, or should wood be wasted in the stump or top a converting 

 factor between 80 and 90 should be used; on the other hand, should the 

 timber be very smooth, straight and be cut in very large pieces a factor 

 between 90 and 100 should be used. 



Directions. 



A. Parties. — Use the same party organization as for Illustration 1. 



B. Equipment Required Per Party. — Use the same equipment as for Illus- 



tration 1, except that Form 1 should be substituted for Form 3 A. 



C. Method of Procedure. 



1. Prepare Form 1 with the following column headings on a separate 

 sheet for each species : 



0. 



D.B.H. 



Total Height 



D.M.H. 



Vol. Cu. Ft. Vol. Cords 



The D.M.H. column will be used for tallying the diameter at the mid- 

 dle of the total height. The D.M.H. and total height of each tree 

 should be tallied opposite its D.B.H. 



Caliper the D.B.H. outside the bark of each tree. 



Estimate, checking occasionally with a hypsometer, the total height 

 of each tree. 



Estimate, checking with a dendrometer if available, the D.M.H. out- 

 side the bark of each tree. 



With the Schiffel formula work up the cubic volume including the bark 

 of all trees and total. 



Divide the total volume of each species in cubic feet by 90 to redu(;e 

 to cords. 



D. RrftTcnccs. — Numbers 51, G4, and tif). 



