68 FOREST VALUATION 



Ge = Yr-f-o (Sc-f E) (i.op r - 8 -i) 



* 



s Oe __ Yr + T 4 (i.op'-- 4 ) (Sc 4- E) (i.op r - 3 i 

 i. op 1 "- 3 



and Ge = 



Yr + T4(l -P r ~ 4 ) (S'C 4- E) (i.op r - i)* 



To get a common denominator for S Ta, treat in this manner : 



Ta(l.0pa i) I.ppr-a __ Ta(l.Opr-a) (i.ppa . T ) 



I0pa(i.op I v I.Opr-a ' I.0p r (l.0p I 



adding we have : 



q. ( r-i ?C (Yr + E + Sc) (l.Opr l)+Ta(l.Opr-a) (i.opa-i) _ ( 



(I.0pr) (l.Op I) 



as the expectation value of the growing stock on the ten-acre, or r 

 acre sample. Dividing this by r the average value of the growing 

 stock per acre is obtained and the formula reads: 



-( r - 1 )Ge average per acre = 



(Yr + E+Sc) (l.0p r - 1)+ Ta(l.opr-a) (l.ppa i] 



r(i.opr) (i.op-i) 



3. To illustrate: Assume an area 16,000; clear cut, and plant, 

 P, 2%. 



Rotation, 80 years. 



Premises per acre : final yield or Yr, stumpage value per acre, 

 $400. 



Thinning at 20 years, no income. 



Thinning at 40 years, $10 stumpage. 



Thinning at 60 years, $20 stumpage. 



1.50 



Current expenses $1.50, hence E = -- , or $75. 



.02 



Cost value of land, Sc, $10. 



*For the class it is helpful to write these out as follows: 



Yr Ta(i.op r - a ) _ QSc 4- E) i.op r - m 



~ i.op r - m i.op r - m i.op r - m i.pp r 



this makes addition of SYr, 2Ta, etc., much easier and clearer. 





