76 PRINCIPLES OF AMERICAN FORESTRY. 



Forest trees seldom do best where they are subject to 

 a strong draft of wind around the trunks. While under 

 some conditions it may be desirable to remove the dead 

 branches from trees, yet even if it is decided to do this 

 in the interior of the forest, it is generally best to leave 

 the borders without such pruning in order to protect it 

 from drafts. 



Forest Weed is a term used to signify any growth that 

 may occur in forests which crowds the other growth and 

 so prevents it from developing to the best advantage. 

 It may apply to raspberry bushes, hazel brush, poplars, 

 and other similar materials which often come in our 

 forests in the early growth of the plantation; or even 

 to large inferior trees which are in the way of the proper 

 development of the better species. But a tree may at 

 one period of its growth be of much value in a forest in 

 producing shade and acting as a nurse tree, while later 

 on in its growth, after its usefulness has been completed, 

 it may be regarded as a weed. 



Thinning is the most important part of the forester's 

 art in securing good timber and in reseeding the land. 

 The ideal condition in the life of timber trees is to secure 

 a natural crop of seedlings so crowded when young as 

 to increase very rapidly in height and produce slender 

 trunks free from side branches. When this crowding 

 has gone far enough the less valuable and weaker trees 

 should be removed to give the better trees sufficient 

 room for their crowns to develop. These remaining trees 

 in the course of a few years will again crowd one another 

 too severely, and this process of removing poorer trees 

 must then be repeated. Then when the final stand of 

 trees is approaching maturity, thinning should be com- 

 menced to let in light and air to produce the conditions 

 under which seedlings develop to best advantage. 



Heavy thinning should be practised only after very 



