CONDITIONS OF DEVELOPMENT. 



39 



Based upon a proper consideration of these practices, it will appear that an average allowance 

 of 30 per cent in saw waste on the volume of logs of all sizes is more than ample, and that the 

 lumber yield given in the following table and computed on this assumption of waste, although 

 being for same sizes even 100 per cent above the log scales in use, remains still below the 

 practically obtainable results: 



Lumber contents in 16-foot lays. 



In estimating the cut of lumber that may be obtained from a given area, there must, to be sure, 

 an allowance be made in addition for unserviceable, crooked, knotty, rotten material, which may 

 reach from 15 to 20 per cent, and, furthermore, an allowance for the loggers' risk in breakages and 

 other losses, which may be figured at 10 to 12 per cent. 



To give, however, an approximate idea of the lumber contents of trees of various diameters 

 and heights, these have been calculated for a number of trees and recorded in Table II, p. 87, 

 in the Appendix. 



From these measurements, which are based upon Doyle's log scale, the following tabulation is 

 made, showing approximately the increase of lumber contents with diameter growth and age. 

 From this it would appear that the greatest per cent of increase occurs during the period from the 

 fortieth to seventieth year, while in the fortieth year the average annual growth in volume has 

 been about one-third of a cubic foot, in the seventieth year it is nearly 2 cubic feet, :>r six times as 

 great, and by the one hundredth year this rate is doubled, centenarians containing about 400 

 feet B. M. During the next century the trees make twice as much lumber wood, for now all wood 

 deposited makes lumber : 



Increase in lumber contents with itze. 



CONDITIONS OF DEVELOPMENT. 



DEMANDS UPON CLIMATK AND SOIL. 



The wide field of its natural distribution and the thriftiness with which the White Pine 

 develops in climates outside of its native home show that it is quite adaptive as far as climatic con- 

 ditions are concerned. Yet, from the manner of its development within the climatic range of its 



