EXPECTATION VALUE. 151 





, T a Xl'0 P 



l'op r -l l'op r -l l'op r -l 



cxl'op w 



+ l - Ft ~~ ^ > 



l'op r 1 



as before. 



Example. Determine the expectation value of a forest now 

 45 years old, if that forest yields the returns given in the 

 money yield table for the Scotch pine at page 122 ; if rotation 

 = 80 years; cost of formation = 60 shillings; per cent. = 2J; 

 and annual costs per acre = 3 shillings. 



l-025 45 (2225 + 67 x l'025 30 +86 x 1'025 20 



-^o 



1-025 80 -! 

 ^F e = 1141 shillings = 57 I 0. 



It was found before : 



At page 127 . 80 S e = 250 shillings. 



136 . *G e = 891 



Total . . 1141 = 57 1 

 as above. 



In the case of the present growing stock being abnormal, 

 the corresponding values must be introduced into the account 

 (see page 137). 



b. Calculation under the supposition that, after the cutting over of the 

 present crop, another species or another method of using the soil is 

 introduced. 



In this case, the value S' of the soil corresponding to 

 the new conditions must be introduced into the account ; 

 then the rotation / must be determined, under which the 



