86 



FOREST VALUATION 



with stands of all ages from i-So years. From this sample we 

 would get each year : 



One acre of ripe stuff to cut or Yr, 



Several acres of thinnings, or 2Tq, 



And we should have expenses of one acre to plant, or c, and 

 80 acres to pay taxes, protection, etc., or re, which may be put into 

 the following form: 

 average net income per acre = 



Yr + 3 Tfl — c — re 



or according to the following table for spruce site II, for a rotation 



of 



583+ 71 — 12 — 54 

 60 years = $ 9.80 



80 years 



60 

 980 + 232 — 12 - 



80 



= $14.10 



Spruce site II, Germany, Endres, after Schwappach, gross in- 

 come, expenses, net income and Se for different rotations from 30 

 to 120 years for use in formula. Average net income per acre 



Yr-|--Tq — C — re 



