IMPROVEMENT OF THE FOREST 199 



for growth, the differences between the development of 

 the individual trees are intensified. It is always the 

 leaders which are best able to spread their crowns, so 

 that many trees that are only partially crowded at first are 

 later on suppressed, and those at first suppressed are at 

 last actually killed. There is, therefore, a rapid reduc- 

 tion of the numbers of trees by the natural struggle for 

 existence. 



The development of a stand in this manner is at- 

 tended with both advantages and disadvantages. The 

 chief advantage is that the crowding results in the death 

 of the lower branches and the production of clear stems. 

 On the other hand, the restriction of the crowns, in both 

 length and width, results in a reduction of the diameter 

 and volume growth of the individuals. \Vhile the trees 

 are young, the retarding of growth is relatively small, 

 because only a small crown is required for growth and 

 the natural vigor of the trees is at a maximum. Later 

 on, there is a progressively greater relative difference 

 between the actual and possible growth through the 

 reduction of the crown. In some cases the crowns are so 

 reduced that they do not occupy more than 1 5 per cent, 

 of the total length of the stem. Such a tree is lanky, and 

 exposed to damage by the wind; it is incapable of good 

 seed production; it is weak and subject to insect attacks 

 and to damage by excessive droughts; and its product, 

 though of high quality, is quantitatively much less than 

 it might be. The crowding of a stand is, therefore, 

 beneficial in youth, as it contributes to the production 



