BENEFITS OF PEUNING. 245 



and even their qualities. We find that when trees are 

 grown singly, and are fully and openly exposed to sun 

 and air, they are, in most instances, clothed with 

 branches from near the surface of the ground to the 

 top, so that the aid of art is called to assist in produc- 

 ing a clean, tall, handsome, and useful tree. Pruning 

 in this case might be almost, if not altogether, 

 rendered unnecessary by timely and judicious thinning ; 

 yet, as already shown, this, in the general management 

 of woods, is found impracticable, and consequently 

 pruning is rendered necessary. The operation of 

 clearing the bole of a tree is the simplest of all depart- 

 ments of pruning, and is performed upon young trees 

 with the pruning-knife ; but in the case of tall trees 

 and those further advanced, the pruning -chisel is 

 employed. 



As a general rule, the trunk of the tree is kept clear 

 of branches to about one-third of its entire height : 

 thus a tree 30 feet in height should have a clean 

 trunk of 10 feet, and a tree 60 feet high, a trunk 

 clear to 20 feet. In low-lying sheltered situations, 

 where the soil is deep, the trunk of the tree may be 

 cleared to nearly half its entire height. Though this 

 is the simplest of all pruning, yet it is in many cases 

 sadly abused by clearing the tree of its branches to 

 near the top, and doing the work roughly and in- 

 artisticaUy. 



It is often found necessary, although not altogether 

 desirable, to prune trees in hedgerows, and along 

 avenues, rides, carriage-drives, and roadsides, not with 

 the view of benefiting the tree, but only to check the 

 growth of the branches, and prevent them from unduly 

 hanging over, shading surrounding crops, and impeding 

 traffic upon roads. In this case the principal duty 



