Ill THE SELECTION SYSTEM. 79 



and is very marked or insignificant according to the state of the 

 iorest concerned. The quality of the produce yielded is also 

 inferior, sometimes even absolutely bad. 



The chief causes of this inferiority are 

 (i) the rapid growth of the bigger trees, which in the case of 



conifers produces soft-grained timber ; 

 (ii) the formation of large knots, which are serious defects 



when they occur in the silver and spruce, firs ; 

 : (iii) the production of various kinds of unsoundness which 

 induce rapid decay in the wood of the species just named. 

 These defects, like the general unsatisfactory condition of 

 the crops, result from the exploitations being spread over 

 too large an area. The consequence is that the damage 

 caused by the felling and export operations is not confined 

 to one locality (in which case it might be easy to repair 

 or mitigate), the commission of all kinds of offences is 

 rendered easy, and the trees that stand out isolated 

 above their neighbours, having their crown exposed to 

 the full force of the wind, are thereby broken uprooted 

 or shaken. Nevertheless, the worst that can be said of 

 silver fir forests worked judiciously by selection is that 

 they are not regular. " 

 Hawley sums up as follows : 



' Whether the method gives a lower increment than other 

 methods of high forest has been a point of controversy abroad for 

 many years. Some authors contend that the greater the area of 

 foliage per tree and the more complete use of available nutrients, 

 resulting from the mixing of young and old trees with root-systems 

 penetrating to different depths, must work for greater production 

 under the selection method. The argument against this is that 

 the retardation of the growth of young and middle-aged trees, 

 through shading by older ones, more than offsets these items. It 

 is not until the last half of the rotation that trees in a selection 

 stand are completely freed from shading by taller trees. Analysis 



