68 FOREST VALUATION 



Ge = Yrfo-(Sc-fEHi.op r - 8 -i) ^ 



8p Yr + T<(i.o P r - 4 ) (Sc + E) (i.op r - 8 n 



and o Ge = Yr + T(i.op f -)-(Sc4-E) 



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



TaCl.Opa l) I.opr-a Ta(l.Op r -a) (i.ppa i) 



J0pa(l.pp I >J I.Opr-a ' I.Opr(l.Op I 



adding we have : 



^ (Yr-f-E+Sc) (i.opr l)-fTa(l.Opr-a) (i.ppa i) ^ 



(i.op'O (i.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) (i.opr i)+Ta(i.opr-a) (i.opa i? 



VOC j E*) 



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 stnmpage. 



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 T -")_ ('Sc 4- E)i.op r -' n (Sc f E) 



~ i.op r -'" " i.op r - m i.op r - m i.op r - m 



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



