PROFITABLE TIMBER TREES 101 



which were not killed soon enough, and a certain proportion 

 which had them killed too soon. The mean between these 

 two extremes is what the forester aims at in thinning. 



But with very slow growth due to poverty of soil, trees 

 cannot attain a great height, and the shorter in height the 

 clean bole is, the smaller the space for putting on knot-free 

 timber. With fast - growing trees and large knots, the 

 farther the latter extend from the axis the more growth 

 must be made to give a certain quantity of clean wood. 

 The production of the latter, composed of narrow rings, is 

 consequently a long process at the best, and, in the case of 

 artificially grown wood, means an expensive process. 



In the case of natural forests it is the result of a 

 combination of favourable conditions which can only exist 

 to a very limited extent, and the time must come when the 

 supply of first-class pine will only be kept up by sylvi- 

 cultural methods, and the cost of production, which is now 

 a more or less neglected factor in fixing the price, will come 

 into play. It will then be seen whether properly grown 

 British Scots fir will be so much behind the imported timber 

 as is now assumed, justly or unjustly, to be the case. 



That the greater part of the Scots fir now put on the 

 market is inferior to that imported, there is little reason to 

 doubt. In the first place, it is seldom planted pure, but 

 either mixed with larch or other conifers, or put in as a 

 nurse to hardwoods, and allowed to stand when the latter 

 happen to fail or become crushed out through neglect. In 

 such cases it is crushed out and weakened when unable to 

 keep pace with the other species, or it becomes branchy and 

 coarse when mixed with slower -growing hardwoods which 

 allow it to develop a large crown. Grown in this way, it 

 is only by accident that it obtains the necessary conditions 

 for growing into useful and high-class timber, and it is little 

 wonder that the timber actually produced has a poor reputa- 

 tion. But even when pure plantations of it are formed, 

 which is very seldom, the production of good timber is often 

 prevented by early or excessive thinning. In colliery 

 districts especially, where small poles can be turned to 

 account, the plantations are often heavily thinned when 

 thirty or forty years of age in order to obtain pit props, 



