104 THE THEORY AND PRACTICE OF WORKING PLANS 



to grow from one class to the next are found by working up the 

 increment borings.* The complete data are as follows: 



Applying the formula, y, the annual cut, 



■■ - — - — Vi = - — X 293 = 1 .674 board feet per acre, 

 fl4-a3 35 



+— I^3=-^Xl72= .637 



QA-as 35 



, «2— W3 -54., z- 



-I -V2=^^X 93 = 1.569 



CI3 — CI2 32 



«1-W2 .04 



H z'i=-— ^X 42= .062 



a2 — ai 27 



Total 



3-942 



(( (( II 



IC II II 



a (( (t 



a (I II 



, z 168.48 bd. ft. per ac. of surplus o i, j r .l 



H — = r-^- -. -^ — = 4.814 board feet per acre, 



^^ 35 years, the cuttmg cycle 



Total annual cut 



= 8.756 " 



(C (( u 



or, for the 1730 acres in this t>'pe= 16,117 board feet of hemlock. 

 Comparing this with the results obtained from similar 

 data by method No. 4, the annual cut does not appear exces- 

 sive. If, however, the result were much higher than those 



* See " A Practical Application of Pressler's Formula," F. Q., XIV, No. 2. 



