198 THE INCREMENT. 



cent.). Pressler went out of his way to call the above expres- 

 sion the approximate value of c p f , whereas it represents the 

 absolutely current value of it, as has just been proved. 



The indicating per cent, (or current forest per cent.) 

 indicates the per cent, with which the capital represented by 

 a wood works at the various periods of the wood's life ; in 

 other words, it indicates at any time, whether a wood is 

 financially ripe or not. (See page 169.) As long as the 

 indicating per cent, is larger than the general per cent, p, at 

 which money can be invested otherwise with equal security, or 

 at which money can be obtained for investment in forestry, 

 the wood is financially not ripe ; when the indicating per 

 cent, has become smaller than p the financial ripeness of the 

 wood is past ; the wood is financially ripe at the time when 

 the indicating per cent, is equal to p. 



It remains to substitute the proper values for w and W. 

 The capital value w of the forest at the present time is 

 represented by the value of the soil and growing stock, 

 correctly = S + m G c - As the formula is only used in the case 

 of woods which are at or near maturity, the utilization value 

 may be substituted for the cost value of the growing stock, 

 so that 



This is the capital which it is proposed to let work for 

 another n years. During that period it increases to the value 

 of the forest in the year ra + n, from which amount must be 

 deducted the annual costs during n years with compound 

 interest, so that : 



W=Y m+n +S-E (l-op-l) 

 and 





If between the years ra and ra + n a thinning has been 



* This formula differs from that given by Pressler and Judeich for the reasons 

 indicated in the footnote at page 163. 



