118 PRINCIPLES OF AMERICAN FORESTRY. 



PRUNING. 



Pruning Should be Avoided as much as possible and 

 yet be done sufficiently to secure the effect desired. If 

 it is begun early in the life of a tree no large branches 

 need ever be removed, the most desirable pruning being 

 the directing of the growth by pinching off the buds that 

 would develop into undesirable branches; but this is 

 impracticable on a large scale, and for this reason, in 

 ordinary practice, it is often necessary to do more exten- 

 sive pruning. 



The Purpose in Pruning Trees is to give them forms 

 that are desirable for the purpose intended. For ex- 

 ample, a tree for the lawn or windbreak may be most 

 desirable when covered with branches even down to the 

 ground, while street trees should have a trunk free from 

 branches for eight or ten feet from the ground. Many 

 of the Evergreens, and some other trees used for ornament, 

 naturally take on so regular and desirable a form that it 

 is not necessary to prune them, except perhaps to pinch, 

 or cut off an extra leading shoot that is likely to make 

 a forked top, while the White Elm, Soft Maple, and others 

 need occasional pruning to remove or shorten awkward 

 branches, at least while the tree is young and growing 

 rapidly. 



The Proper Time for Pruning is determined by the 

 effect of the operation upon the health of the tree. Dead 

 branches may be safely removed at any season. The 

 removal of live branches during the growing season less- 

 ens the leaf surface and hence checks growth. Pruning 

 when the tree is dormant results in a more vigorous growth 

 in the remaining branches. Wounds made by pruning 

 just as trees are starting into growth do not heal over 

 as readily as those made eailier in the spring or during 

 the period of active growth in June. Wounds made 



