158 THE FINANCIAL RESULTS OF FOKESTUY. 



where C represents the capital which has produced the amount 

 / in the shape of interest. The per cent, is then 



per cent, p = ,, X 100. 



This formula is used in the case of forestry, and it remains 

 only to introduce the proper amounts for / and ( '. In other 

 words — 



The current annual rate of interest is equal to the net 

 annual value increment of a wood divided by the cost value 

 of the wood at the commencement of the year in (juestion. 

 The current annual per cent, is equal to that quotient 

 multiplied by 100. 



Let— 



y„, be the utilisation value of a wood at the end of the year )ii, 



y.u+i „ „ „ „ „ „ „ M "'+1, 



then — 



-* //I -r 1 -^ in 



represents the increase in value, which has been produced during 

 the year iii -{- 1. Deducting from this e, the annual costs, the 

 net increase in value is equal to — 



The cost value of the wood at the end of the year iii (or 

 beginning of the year in + 1) is represented by — 



(a.) The value of the soil with compound interest to the 

 year in =^ .^ -, r^ , , 



{b.) The cost of formation with compound interest to the 



y^"'' '" = .• X 1-Oir. 



(c.) The value of the annual cosLs during in years with 

 compound interest calculated for the end of the 

 year in = 



ia5C^) = ,:a-0;r-i). 



'Op 



