100 EOTATION rOR NATIONAL EXPLOITABILITY, 



total of production of which it is capable at a much earlier age. la 

 order to obtain the highest average yield possible of produce, that 

 is at the same time the most useful the forest can produce, are we to 

 exploit it at an age intermediate between the two ? ' Certainly not. 

 It is at the age of maturity itself that we must exploit it, just as we 

 do wheat, fruits and other produce of the soil in general. 



We know that the average sum of production of the soil of a 

 canopied forest decreases but little so long as the forest is full and 

 composed of vigorous and healthy trees. Let ua now enquire in 

 what way the usefulness of this production increases with the age 

 of the forest. The variety of purposes to which any piece of timber 

 is applied, depends principally on its size. Timber dealers hence 

 divide the various descriptions of wood in the market into size- 

 classes, depending chiefly on diameter. The highest class of course 

 commands the highest prices, for no piece of wood is placed in that 

 class, unless it is suited for employment in the most important 

 industries. It is impossible to estimate directly the value which 

 wood commands in any single one of these industries, since that 

 depends not only on the use made of the wood in that particular 

 industry, but also on the relative quantities of such wood consumed 

 by them severally, so that this value is subject to great fluctuations 

 according to time and place. Hence the most logical classification 

 of woods must be founded on the price of unity of volume. As long 

 as the selling rate of any class of wood has a general and steady 

 tendency to rise, we may be sure that it is required by certain in- 

 dustries, which are willing to outbid all others in order to obtain 

 it. That industry will pay more for it, which is most in want of it. 

 From what precedes, it is thus clear that the utility of wood goes on 

 increasing continuously with its size until it reaches the first class 

 of commerce. 



The same result is obtained if we compare the receipts realized 

 at different ages. The value of the standing timber on a given area, 

 from its first appearance to the time the trees attain the first class 

 size of commerce, does not increase in exact proportion to its age, 

 but more rapidly. For instance, if the total value of the crop at the 

 latter age, say in this case 160 years, is £2000, and at the age of 

 120 years £ 1500, then at the age of 80 years, it would be very far 

 from fetching £1000. Thus an increase of marketable value is a 



