112 FOREST PLANTING. 



ages grow up together, the conditions for natural thin- 

 ning out are more favorable. Here, nature itself does 

 the principal work of timely thinning out, and the 

 elementary forces do as is generally known less dam- 

 age in forests where conifers are intermixed with 

 foliaged tree?, than in forests of pure stock. And still 

 the helping hand of the forester can do a great deal to 

 produce a quicker development of the trees and to in- 

 crease their strength and growth. 



It is an old rule in forestry to commence thinning early, 

 and repeat it often, but always to do the work moderately. 

 But after the lapse of from 60 to 70 years, when the 

 trees have attained their full height, it is expedient to 

 open out the stock itself more freely, in order to give the 

 trees a chance to extend their remaining branches, and 

 thus enable them to accelerate their accretion of wood. 

 The brunches of trees in forests under sixty years of age 

 should be allowed to grow pretty close together so 

 densely as not to show any gaps. Such forests will 

 produce the best timber, as the trees then will develop 

 branches only on the higher part of the trunk, leaving 

 the lower part free, and yet keeping the soil well shaded. 



Absolute rules as to the exact time for the periodical 

 thinnings cannot be given, except that the soil should 

 always be protected from light, sun and wind, and that 

 the vigorous growth of those trees which are intended for 

 future stock, should never be interfered with by their 

 companions. Which trees should be selected in thin- 

 ning out a forest, can best be shown in forests witli a 

 pure stock of trees, *'. e., with, trees of the same kind 

 and mostly of i he same age. Here you find three dif- 

 ferent classes of trees, viz. : 



(1) The dominant, which have grown ahead of the 

 others. 



(2) The governed, which, although lifting their crowns 

 in the sunshine, are narrowed in by the other trees. 



