COVERIXG HOLES IX TREES. 189 



answer the same purpose. These fabrics are not materially 

 affected by the movements of the tree, and if well tarred are 

 not often bored through by insects, as the tar is repugnant 

 to them. 



In many cases such cavities as are exposed by the sawing 

 off of laro'e hollow stumps of broken branches may be covered 

 to advantage with tin or zinc, which must be tacked closely 

 over the cavity and afterwards painted or tarred. (See Fig. 

 26. ) If these coverings are applied in the win- 

 ter, it may be necessarj^ to use in connection with 

 them some such substance as the insect lime, in 

 order to prevent the escape of the young cater- 

 pillars in the spring. This substance may be 

 smeared around the edge of the tin or Ijurlap in 

 such a manner as to close every crevice comnui- 

 nicating with the cavity. It has also been used fig 26. 

 to stop small holes in trees, and will answer the '^'""''^ '''''^"^" 

 purpose temporarily, but it must be occasionally smoothed 

 over, as it shrinks and cracks in a short time. 



Scraping Trees and Removing Loosened Bark. 



Scraping the loose outer bark from old trees facilitates 

 the discovery of the eggs, larvte and pupre. of the gypsy 

 moth. Such scraping leaves the surface of the trunk and 

 larger branches in a comparatively smooth condition, and 

 deprives the caterpillars of their places of refuge, causing 

 them to crawl down and seek shelter under the burlaps. 



If in dealing with fruit trees the loose bark only is scraped 

 off and burned, the main object is accomplished. Such scrap- 

 ing l)enefits orchard trees by the removal of mosses and 

 lichens and the eggs and hibernating forms of injurious 

 insects. 



An implement modelled after the scufHe hoe is useful for 

 this work. (Fig. 27.) Its blade being double-edged, it may 

 be used with both the upward and downward motion, and by 

 means of a long handle the trunk and branches of the fruit 

 trees may be reached to a height of from twelve to eighteen 

 feet from the ground. The ordinary "three-cornered" 

 scraper is also much used. It is believed that this loose 

 outer bark forms a protection to the tree from the cold of 



