52 



TREE PRUNING. 



even if adhering to the wood, is left without direct 

 communication with the leaves, it must die and 

 decay. A coating of coal-tar should, 

 of course, be applied to such wounds. 



Loosened Bark. It is necessary to 

 frequently examine the lower portions 

 of the trunk, especially of trees begin- 

 ning to grow old ; for here is often 

 found the cause of death in many trees, 

 in the large sheets of bark entirely sepa- 

 rated from the trunk. This condition 

 of things, which often cannot be de- 

 tected except by the hollow sound pro- 

 . 49. duced by striking the trunk with the 

 back of the iron pruning knife, arrests the circulation 

 of sap, while the cavity between the bark and the 

 wood furnishes a safe retreat for a multitude of in- 

 sects, which hasten the destruction of the tree. The 

 dead bark should be entirely removed, even should it 

 be necessary in so doing to make large wounds. 

 Attention, too, should be given to injuries to the 

 bark caused by the fall of neighboring trees. These 

 may remain hidden for years, and are often only 

 detected by the peculiar sound produced by a blow 

 of the pruning knife. Cases of this nature require 

 the treatment recommended for the last class. 



Cavities in the Trunk. Very often when a tree has 

 been long neglected, the trunk is seriously injured by 

 cavities caused by the decay of dead or broken 

 branches. It is not claimed that pruning can remove 



