Thinning Plantations 149 



growth should have the trees branchless for about one-half 

 of their height, which is, of course, brought about by crowd- 

 ing, and at forty years three-fourths of the trunk should be 

 clear of branches. 



I have purposely abstained from giving the number of 

 feet apart at which trees ought to stand at various stages 

 of their growth, and the number of thinnings they require, 

 as being likely to prove misleading. 



4. The question as to which trees should be removed 

 need cause little or no anxiety, as the dead, dying, diseased, 

 and badly-formed will naturally receive first attention. 



In thinning, the following short rules should be ob- 

 served : 



1. Thin not at all until the undergrowing vegetation has 

 been completely killed out by the overhead foliage, the 

 golden rule of sylviculture being to keep the sunshine off 

 the ground until near the end of the tree's career. 



2. Thinning should be performed in such a manner as 

 not to reduce the value of the crop, but so as to tend to the 

 production of the greatest quantity of the most valuable 

 timber in the shortest possible space of time. 



3. By thinning allow of sufficient light and air to prevent 

 the trees becoming drawn up and lanky, but avoid too 

 much space, which induces the growth of side branches and 

 detracts from the value of the timber. 



4. Keep up the number of trees to the highest possible 

 pitch until they are tall, straight and clean, and thin 

 gradually. 



5. The danger of suddenly exposing the trees to currents 

 of cold air to which they have hitherto been unaccustomed 

 must be carefully guarded against and it is a serious mistake 

 to thin in an abrupt or unequal manner. 



6. In thinning remove all dead and dying trees first, then 

 the distorted and stunted, the best grown and healthiest 

 being preserved for the permanent crop. 



7. Hard- wooded trees require proportionately more space 

 for development than conifers, and the annual rings in the 

 timber of the latter should be narrow in proportion to those 

 of the former, good quality of hard- wooded timber being 



