15 



middle and small end diameter of each bolt being recorded. 

 The cubic foot volumes of the sample trees were then cal- 

 culated by Newton's formula (B+4bj-fb)-. The cubic foot 



6 



and cord volumes of the plots were calculated by the use of 

 the volumes of the mean sample trees. The cubic foot and 

 cord volumes were also computed by both the original and the 

 revised red maple volume tables using the original tally of the 

 plot to find the number of trees in each diameter class by 

 which the volume of a single tree in that class, as found in the 

 red maple table, was multiplied. The quarter-acre plot was 

 then cut clear and piled as four-foot wood, the measurement 

 of the piled wood giving the actual volume of the stand. 

 Results of the test are given below. 



Method Yield per 1 acre Error 



Actual volume cut 5.725 cords 



Revised volume table 5.772 " .83% . 



Original volume table 5.822 " 1.70% 



Mean sample tree method 5.935 " 3.84% 



This test shows not only that the use of the volume table 

 was more accurate than even a very carefully executed 

 sample tree method but also that with even-aged second 

 growth stands it can be applied according to diameter breast 

 high and height regardless of species. Cubic foot and cord 

 volumes in the yield tables are derived by harmonizing with 

 a curve the sums of the volumes of the individual trees on 

 these plots as determined by the revised red maple volume 

 table. 



Forest Form Factor. A forest form factor is the ratio be- 

 tween the volume of a stand and that of a cylinder having the 

 basal area of the stand and the height of the average tree. 

 It is most easily expressed in cubic feet. Those here given are 

 breast-high, merchantable, cubic foot forest form factors 

 obtained by multiplying the basal area of the stand by the 

 average height of the dominant trees and dividing the yield 

 per acre in cubic feet, as given in the yield table, by the 



