868 NATURAL REGENEKATIOK BY SICKD. 



unsound, or are unlikely to continue sound till the next exploita- 

 tion ; (b) perfectly sound ones which stand over advance growth 

 and have attaiaed exploitable dimensions, and fcj, if the quantity 

 of timber obtained from classes (a) and (h) make up less than the 

 annual yield, also the less valuable and less promising individuals 

 of smaller size which interfere or threaten to interfere with the 

 growth of the trees of the future in over-crowded places.* Trees 

 falling under class (a) must be marked first, the balance being 

 taken from the other two classes. If the balance to be made up 

 is small or even nil, no drawback will ensue, since the removal of 

 so many trees of class (a) will in any case let in the amount of 

 light required. The thinning out of over-crowded places is designed 

 directly to help the growth of the more valuable individuals ; at 

 the same time it indirectly contributes towards the appearance of 

 advance growth. If we do not thin, nature herself will effect the 

 thinning, but not until the surviving stemg have lost much time 

 and some of their vigour in gradually suppressing their neighbours, 

 and these, being dead and more or less decayed, have lost most of 

 their value as timber. Moreover, in a natural thinning there is no 

 guarantee that it will be the most desirable species that will -van- 

 quish in the struggle. Hence, even if there is no sale for the 

 stems that require removal, they can at any rate be got rid of 

 by girdling, the slight expense of which operation will be covered 

 several times over by the improved production of the forest. 



If the forest is of limited extent, it is impossible to avoid going 

 over the entire area every year ; but if it is sufficiently extensive, 

 it should be divided into 5-20 coupes, which will be worked succes- 

 sively in rotation, so that each coupe may enjoy complete rest tor 

 a number of years, during which the young growth will have time 

 to recover from the felling and export operations and continue to 

 push on unmolested. Numerous coupes, by concentrating the 

 fellings, will also facilitate export and supervision. The number 

 of coupes will be directly proportionate to the extent of the forest, 

 the quantity of sound exploitable stock, the slowness of regenera- 

 tion, the shade-enduring capacity of the component species, the 

 time which the seedlings take to establish themselves, the amount 

 of unavoidable damage in the exploitations and the tardy recovery 

 of the stock therefrom, and the caution which the nature of the 

 climate and locality and the mode of growth and the sensitiveness 

 to injury from exposure of the species in question impose on any 



*See alao uuder Ordinary Thinnings in Book III. 



