INTRODUCTORY. 275 



occur, however, where it is desh-able to interrupt the leaf 

 canopy at a certain age so as to form open woods ; in such 

 cases separate steps must be taken to preserve the fertihty of 

 the soil. 



Again, during the lirst part of the life of a wood it is subject 

 to special dangers, most of which disappear later on, when the 

 attention of the forester must be directed to other matters. 



The subject may, therefore, be divided into the following 

 three chapters : — 



Chapter I. — Tending of Woods during Early Yolth. 



,, II. — Tending of Crowded Woods after Early 



Youth. 



,, III. — Tending of Open Woods for the Produc- 

 tion OF Large Timber. 



T I 



