M f State College 



24 «'• *" PRELIMINARY CALCULATIONS 



D. The Cubic Contents of Branches. 



A branch is treated as a cylinder whose diameter is equal to the diam- 

 eter of the middle of the branch. Letting Bi equal the middle diameter 

 and L the length, the formula becomes, 



BiXL. 



Directions. 



A. Data Required. — Use the data collected in Problem 6. 



B. Method of Procedure. 



1. Compute the contents of one tree according to the formula) given in 



the Explanation. 



2. In the remaining data use, in place of the formula for basal areas, the 



table of basal areas given in the Appendix (Table IIL). 



3. Tally all volumes in the proper column on the analysis blank and total. 

 Illustration 2. — To Compute the Cubic Contents of Felled Trees by Cubing 



the Tree as a Whole (Schiffel Method). 

 Explanation. — The following formula for securing the full stem volumes of 

 trees, devised by Professor Schiffel of the Austrian Experiment Station, has 

 recently been introduced in this country. 



Cubic contents of a tree = (0.16 B-\-O.QQb)H, 



where J5=area in square feet at the D.B.H. point; 



h = basal area in square feet at the middle of the total height ; 

 H = total height in feet. 



This formula is explained in the ''Centralblatt fiir das gesamte Forst- 

 wesen" for December, 1906. It has not yet gained general use in the United 

 States as its accuracy has not been completely established. This illustra- 

 tion serves to compare its accuracy with the SmaUan method of cubing trees. 



Directions. 



A. Data Required. — Use the same data as in Illustration 1. 



B. Method of Procedure. 



1. Compute the cubic volume of one tree using the Schiffel formula. 



2. In the remaining data use tables Number I and II in the Appendix 



for finding value of 0.16 B and 0.66 b. 



C. References. — Numbers 28, 29 and 31. 



D. Discussion. 



1. Comment on the relative accuracy of this method as compared with 

 that of cubing each section separately outlined in Illustration I. 



