198 A MANUAL OF FORESTRY. 



The operation demands the forester's special attention, 

 since it is much easier to produce a proper mixture at 

 this early period of life than later on. 



SECTION II. TENDING OF CROWDED WOODS AFTER 

 EARLY YOUTH. 



When the trees, which compose a wood have become 

 sufficiently large to close up and form a complete leaf- 

 canopy, several sources of injury disappear. Weed 

 growth has ceased to affect the trees, and dangers from 

 frost and drought have been reduced to a minimum. 

 Danger from fire is not so acute as during the early 

 period of life, and in a temperate climate it may 

 disappear altogether, especially with broad-leaved 

 species. On the other hand, danger from insects and fungi 

 continues, while strong winds, snow and rime may break 

 or throw down trees ; such damage may extend over 

 considerable areas. 



While the forester may thus be relieved of some cares 

 peculiar to infancy, his woods require tending in other 

 and very important directions. He must now direct his 

 attention more particularly to giving to each tree that 

 growing space best suited to its further development, 

 without sacrificing the full activity of the soil ; he must 

 also take measures to insure a high technical utility to 

 the material under production. 



The principal sylvicultural measures by which justice 

 is done to the above-mentioned requirements may be 

 arranged under the following three headings : 



