ORNAMENTAL AND SHADE TREES 



A Department for the Advice and Instruction of Members of the American Forestry 



Association. 



Edited by J. J. Levison, B. A., M. F. 



Arborculturist Brooklyn Park Department, Author of "Studies of Trees," and Lec- 

 turer on Ornamental and Shade Trees, Yale University Forest School. 



HICKORY TREES THREATENED 

 WITH DESTRUCTION 



A 



RE we to lose our hickory trees 

 in much the same fashion as we 

 have already lost our chestnut 

 trees? Unless municipalities 

 and the owners of woodland property 

 will do something in a concerted way 

 to protect the hickory trees, we shall 

 lose them soon. Thousands of hickory 

 trees are already dead all over Long 

 Island and for hundreds of miles north 

 and northwest of New York City. 



The enemy is the hickory bark borer, 

 officially known as "Scolytus quadris- 

 pinosus" which is a small black beetle 

 that bores in the inner bark of the tree 

 and then girdles the tree with a series 

 of galleries preventing the flow of sap. 

 The insect works at a comparatively 

 fast speed and often trees die in the 

 same year they are attacked by the 

 borer. 



From October to early May the 

 borer is a grub located in small galleries 

 in the bark. Through the winter it 

 gradually enlarges these galleries until it 

 has completely encircled the tree. This 

 period of the insect's life is the best time 

 to check the spread of the trouble. 

 Working underneath the bark, the 

 insect is naturally inaccessible for treat- 

 ment except by cutting the infested trees 

 down and burning the bark. If the 

 infested part of the tree or the whole 

 tree is burned at this time, the colony 

 of borers will be destroyed before they 

 have a chance to enter other trees and 

 begin work on them. It is by working 

 against the insect during this period 

 that we have been successful in saving 

 the hickory trees in Prospect Park, 

 Brooklyn while every other method has 



failed and the hickory trees all around 

 on the outside of the park have died. 

 From early May through June the 

 grub emerges in the form of a beetle. 

 Then it feeds upon the stems and bases 

 of the young leaves of the tree. The 

 writer has tried to spray the hickory 



a 



Work of the Hickory Bark Beetle 

 this is the surface of the wood beneath the 



BARK SHOWING (a) THE PRIMARY GALLERY 

 AND (B) THE LARVAE MINKS 



797 



