38 SHADE TKEES. 



Street trees must be made to develop so that they will not 

 interfere with traffic, and in such a way as to make the best 

 use of existing light conditions. This is accomplished by 

 pruning. Subject to differences necessitated by abnormal 

 conditions, a tree which has been skillfully pruned for a 

 number of years will approximate the following description : 



1. There will be a primary frame consisting of from one 

 to three axillary branches, the number depending upon the 

 species. A tulip or pin oak will have a single axis, while an 

 elm or maple will have two or more co-ordinate members. 

 A properly 2. Grouped about the primary frame will be 



farmed i i i i 



tree. several less imposing branches so arranged as 



to form a symmetrical frame work and characteristic of the 

 species. 



3. Each branch and branchlet will be free from physical 

 contact with its neighbors. 



Unless the tree has had proper care from the time it was 

 planted it will fall far short of this ideal, and quite heroic 

 methods may be necessary to overcome the neglect of years. 

 The commoner rules for pruning may be summarized as fol- 

 lows: 



AT THE TIME A TREE is PLANTED. 



1. The object of pruning at planting is to make the tree 

 live. If it is necessary to sacrifice form to secure this re- 

 sult, do so. After a tree is thoroughly established its growth 

 to the proper form can always be accomplished. 

 pruning - ^ tne r ts are intact it is not necessary 



for life. to p riine the crown. It is seldom, however, 



that such is the case, and the removal of from twenty-five to 

 fifty per cent, of such branches as are not needed in the 

 shaping of the crown will be a wise precaution to counteract 

 root injury. 



3. If any of the roots are broken remove the injured parts 

 by making a clean cut. Balance this cutting by removing a 

 slightly greater relative proportion of the crown. Sometimes 

 it will be necessary to remove practically the entire branch 

 system to obtain a proper balance. (See Figs. 6, 7 and 8.) 



