76 



THE THEORY AND PRACTICE OF WORKING PLANS 



the time of revision, shows an unintentional increase, the cut 

 was set too low. 



(b) Example. — It is desired to determine the cut of hemlock 

 in the slope tj-pe of Catskill forest illustrated by the stand 

 and stock tables quoted above from Bulletin ii of the N. Y. 

 State Conserv^ation Commission.* A breast-high diameter 

 limit of 12 inches is to be observed which, according to U. S. 

 Dept. of Agriculture Bulletin 152, new series, "The Eastern 

 Hemlock," table 10, corresponds to a rotation of 160 years. 

 The current annual increment per cent has been determined 

 from increment borings and Pressler's formula. The com- 

 plete data are as follows: 



D. B. H., Inches. 



C. A. L. Per Cent 

 (Pressler). 



Volume on Average 

 Acre (Stock Table). 



C. A. I. per Acre. 



7 

 8 



9 

 IP 

 II 

 12 



13 

 14 

 15 

 16 



17 

 18 



19 



20 

 21 



Per Cent. 

 7.19 

 4-3° 

 4.00 

 2.69 

 2.68 

 2.26 



2.08 

 1-75 

 1-55 

 1.69 

 1.48 

 1.24 

 1. 10 



•97 



Board Feet. 

 6.80 

 6.41 



Board Feet. 



17.98 

 24.09 

 28.83 



26.68 1 

 21-45 



> X 



> y 



18.36 

 22. 23 

 20.51 

 13.60 



7.78 



(Cent, in st'k table) 

 See p, 48. 



Totals 



276 

 487 

 484 

 64s 

 652 



555 

 376 

 240 

 310 

 329 

 254 

 150 



076 

 1^-6 



• xi 



478 



To summarize: 



7 = 138.31 board feet per acre 

 Z= i68.48 

 F+Z = 3o6.79 



* Bulletin ii, " Forest Suney of a Parcel of State Land," i\lbany, N. Y., 1915, 

 Tables 4 and s- 



