FUTURE VOLUME BY MEANS OF GROWTH 77 



4. Determine the present full-stem volume (inside bark) and the volume 



10 years ago, of each bj^ means of 10-foot sections, and average. 



5. Determine the growth per cent by substituting in the formula th.e 



values obtained in 4. 



6. Calculate from the growth per cent what the volume of the tract 



(assume 40 acres) will be 10 years hence. 

 Method 2. — By Comparing the Average Volume Growth for the past 10 

 years as interest to the Average of the Present Volume and the Volume 

 10 years ago as Principle. 



DiRECTION.S: 



A. Formula. 



V-v V+v 

 n 2 



V-v 200 



V-\-v n 



The symbols are the same as in Method 1. This is considered the most 

 satisfactory formula for all general purposes. 



B. Method of Procedure. 



1. Proceed as in Method 1 using the same felled sample trees. 



Method 3. — By Comparing the Average Volume Growth for the past 10 

 3^ears as interest to the Volume one year ago as principle. 



Directions: 



A. Formula. 



n \ n I 



V-v 



V = X 100. 



^ F(n-1)+^' 



B. Method of Procedure. — Proceed as in 1 and 2, using the same felled sample 



trees. 



C. Di'iC'i'ifiion. 



1. Present the mathematical derivation of each of the formula) used. 



2. Arrange the results of the three methods in a comparative series. 



Give your opinion of their relative values. 



3. Which of the above methods are applicable to mature, and which to 



young stands? 



4. Outline a method of ])r()cedur(' for use in mixed stands. 



5. Are any of the above methods applicable to uneven-aged stands? 



If not, why not? 



100, 



