70 FORESTRY 



cross section paper over the corresponding ages. The 

 curve may serve the purpose of getting a better average 

 from figures which do not run evenly since the irregulari- 

 ties may be evened out, and new values read from such a 

 curve. 



This method is commonly used in preparing tables of 

 volume and of growth. 



X. FOKEST VALUATION. 



When regular crops of trees are produced from forests 

 which have been under management so long that the 

 stands are even-aged and are producing the greatest pos- 

 sible amount of wood, the yield can be predicted with some 

 certainty. The market value of the product cannot be 

 foretold except that it will probably be more valuable than 

 the same class of product is at present. The expenses 

 of planting, protecting the stand from fire and insects, thin- 

 ning, and other care, and the probable amount of taxation 

 can all be closely approximated from actual experience. 

 From these data European foresters have calculated the fi- 

 nancial returns from forest crops basing their profits on the 

 margin left after paying all the expenses of the crop from 

 its inception until it is cut, with compound interest on every 

 item, at a fixed rate of interest. Such calculations cannot 

 be employed in America except for similar conditions. 

 For a plantation it is possible to compute the probable re- 

 turns if we can assume the costs, yield and sale value. Such 

 figures can always be made conservative so that we may 

 be sure that the indicated profits will probably be exceeded. 



The most profitable time to cut a stand of timber is 

 shown by these figures, which is, of course, the age at which 

 the largest rate of interest is earned on the money invested. 

 Stands continue to increase in yield to an advanced age. 

 The value of each unit of wood also increases as the trees 

 grow larger and produce clear timber, and there is a prob- 

 able increase in general prices for wood independent of 



