NORMAL GROWING STOCK. 147 



in the first part of the formula, it reduces to : 

 Y r +T a +. . . 

 'op 



f) 



or, as = , 



Y r +T a + . . 



'op 



In words : The expectation value of the growing stock of 

 a normal working section is equal to the capitalized annual net 

 income minus the value of the soil. 



For the unit of area the formula is : 



Y r +T a + . 



rx 'op 



8. Cost Value of the Normal Groiving Stock. 



Assuming the same conditions as before, and also that only 

 the a year old gradation has given an intermediate yield, the 

 values of the successive age gradations come to : 



G C =(S+E) (l'op 



1 G C =(S+E) (l'op l 



etc. 

 a G c =(S+E)(l'op a - 



a+l G c = (S+E) (l'op a+l -l) + c x l'op a+l -T a x I'op 



etc. 

 r ~ l G c =(S+E) (l'op r ~ l - 1) + c x l'op r ' l -T a x l'op r - a ~ l . 



The sum of these expressions comes to : 



(S+E)(l'op + l'op l + . . 



-op 'op 'op 



By introducing now the further intermediate returns 



'op 'op 



L 2 



