144 North American Forests and Forestry 



cuttings. These sums, together with the cash 

 received at the final harvest, must evidently be 

 equal to the cash outlay with compound interest 

 at the usual rate ; else you would have done better 

 if you had invested your money differently, and 

 your forestry has not been a financial success. 

 Strictly speaking, we must consider still another 

 factor in order to judge of the profitableness of the 

 enterprise. It may be that the land you maintain 

 as forest has risen in value to such an extent that 

 you would have realized more from a sale of the 

 land than from your wood crop. At any rate, the 

 increased market value might be taken into con- 

 sideration, but I believe that it is neglected in the 

 calculations of most forest estates, the world over, 

 principally because there are often motives for not 

 disposing of the land aside from the hope of larger 

 returns by holding it. 



The longer the interval between the beginning 

 of forest growth and the final harvest, the greater 

 is, manifestly, the amount of cash that must be 

 received in order to make a profit on the invest- 

 ment. The increase of cash is, generally speaking, 

 determined by the increase in the volume of wood 

 contained in your forest. Now we see how we 

 can find the upper age-limit for felling our trees. 

 We have learned that after a certain age the 

 amount of wood annually formed gradually de- 

 creases. The time for cutting most profitably is, 

 therefore, the year when the increase in volume 

 of wood no longer exceeds the annual cost of 



