142 TREES AS GOOD CITIZENS 



Since the object of pruning is to promote vigorous 

 and symmetrical growth, it is well to be guided by the 

 principle that the aim is to produce a primary frame 

 toward the center, with a surrounding framework. The 

 primary frame will consist of one or more main branches 

 from the stem, while about this will be several smaller 

 branches grouped in a way to form a symmetrical outer 

 framework. The primary frame should be in harmony 

 with the habits of growth belonging to the particular 

 species. Branches which do not conform to the character 

 istic shape of the species, and cannot be made to conform, 

 should be removed. Branches which develop too rapidly 

 to harmonize with the general framework may be held in 

 check by removal of their ends. These steps develop 

 the tree along lines in keeping with the natural growth of 

 the species. This is always desirable, since pruning is not 

 intended to alter the normal form of the tree. The 

 best pruning is that which leaves the tree most natural in 

 appearance, and in the long run makes it look as if it had 

 not been pruned at all. An exception to this general rule 

 is to be made, of course, in trees trimmed into formal 

 shape and small size for narrow, crowded streets. Trim 

 ming for this type of trees should always be done by an 

 expert. 



It is important that the trees should have a proper 

 height of branching above ground and that the trees 

 should be uniform in this respect. To achieve this it is 

 necessary to pursue a policy of gradual removal of the 

 lower branches. The removal of the lower branches 

 should proceed with the growth of the tree from year to 

 year, so that within a few years there will be 10 or 

 12 feet of the trunk free from branches. This height is 

 necessary in street trees for the freedom of traffic, and 

 it is also important in the matter of appearance. Trees 



