106 



PRINCIPLES OF AMERICAN FORESTRY. 



separated from the parent plant and there take root and 

 grow. These are cut off from the main plant in autumn 

 or spring and form new plants. Almost all trees and 

 other plants can be rooted in this way, but while some 

 root very easily, others require so long a time to do so 

 as to make it impracticable with them. 



The growing of trees from layers is seldom practised 

 in this country, but in some European nurseries it is 

 a common means by which to increase special varieties 

 of trees. For this purpose what is commonly known as 

 mound-layering is often used. This consists simply of 



Fig. 27. — Showing method of mound-layering. 



drawing the soil up around the sprouts that come from 

 the stump of a tree, covering the base of them about 

 a foot in depth. It may be done at any time of the 

 year after the sprouts are two or more feet high, but 

 preferably in the spring. After the sprouts have become 



