98 ELEMENTARY FORESTRY. 



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 lessens the leaf sur- 

 face, and hence checks growth. Pruning when the tree is dor- 

 mant 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 earlier 

 in the spring, or during the period of active growth in June. 

 Wounds made in autumn or early winter generally heal over 

 well, but are more likely to cause bad injuries than if made at 

 the close of the winter. These considerations and practical expe- 

 rience have brought about the following conclusions as to the 

 best time for pruning: 



I/arge Branches are Most Safely Removed during the 

 latter part of winter, before growth starts. Small branches may 

 be safely removed at this time, or during the growing season, 

 preferably about the middle of June; but such very hardy trees 

 as the Elm, Ash, Boxelder, White Willow and Cottonwood 

 may be safely pruned at any time in autumn, winter or spring, 

 while the Mountain Ash, Apple, Plum and Wild Cherry are lia- 

 ble to injury if pruned at any but the most favorable seasons. 



Among the Directions to be Followed in Good Prun- 

 ing are the following: 



(1) Do not' cut off a single branch unless you have a good 

 idea of what you wish to accomplish and the probable effect of so 

 doing on the tree; better not prune at all than to do it without 

 considering the consequences. 



(2) Avoid doing very much pruning at one time, especially on 

 small street trees, which, if they have all their branches removed 

 from the trunks to their final height, are likely to make too much 

 growth at the top for the trunk to support well in high winds. 

 A better way is to remove a part of the lower branches and 



