10 TREE PRUNING. 



It follows that a wound caused by the amputation 

 of a branch must, in order to heal properly, be made 

 perfectly even with the trunk, that 

 every part of its outer edge may be 

 brought into direct communication 

 with the leaves through the net- 

 work of cells destined to convey 

 the descending sap. Although this 

 theory rests on one of the most 

 elementary principles of vegetable 

 physiology, it has not been applied 

 , before to practical forest manage- 

 the loss of a men t. The amputation having 



large branch broken by the 



wind. been made even with the trunk 



in the manner explained, new wood will soon appear, 

 forming first round the top and sides of the wound, 

 which is soon completely surrounded by the new 

 growth ; the wound is gradually healed over, and 

 the decay of the trunk prevented. The time required 

 for the complete healing of a wound depends, of 

 course, upon its dimensions and the natural vigor 

 of the tree. 



The principle being established that large wounds 

 can be made without injury to the tree if care is 

 taken in the manner indicated to prevent decay, it 

 is easy to show the advantage of cutting off injured 

 branches of any size. It is preferable to avoid, of 

 course, the necessity of making large wounds by 

 properly pruning trees when young. All foresters 

 agree that trees should be trained when young, but 



