THE VALUATION OF FORESTS 91 



Should the value be sought for the year a, and this year be 

 but one year previous to the cut, the value of the forest is dis- 

 counted n a, or one, year. As a is dated earlier and earlier 

 in the life of the stand, the discount period n a increases, until 

 when a = o, just after the f elling of the old crop and previous to 

 the starting of the new one, we get the smallest value to which 

 the property shrinks in the entire rotation. 



With the advance of the date of calculation to the year a, 

 both the future yield 7 and the cost of planting C occur first 

 in n a years. The annual expenses, since they are calculated 

 for the same interval, and extend to infinity in both cases, have 

 the same capital value E. 



By Formula Xa, the value of the forest is 



(D) 



Items of either income or expense occurring at other than n 

 years will fall either previous to or subsequent to year a. Those 

 preceding a are not considered in the value of the standing crop 

 (68), but their occurrence in the subsequent rotations affects 

 the value of the forest. 



A thinning occurring in the year r subsequent to a has a value 



T 



at present (year a) of 

 r ~ 



The sum of future values (Q 4 ) is 

 T r 



j. I.0p n - 



i.op n 



A thinning occurring in the year p previous to a^ has a present 



value (year a) of ^ 



u ' i.op p+n ~ a 



