a tree makes continuous demands upon the soil and that each year 

 some of the plant-food originally in it is exhausted. As a tree in- 

 creases in size, it therefore finds increasing difficulty in securing an 

 amount sufficient to keep it in health and vigor. 



It happens frequently, also, that when digging trenches for water, 

 gas or other pipe lines, roots are cut and much of a tree's feeding 

 surface is absolutely destroyed. Furthermore, leaky gas pipes poison 

 the soil; sometimes only a little, sometimes to an extent sufficient 

 to kill all neighboring roots or even entire trees. 



In other cases, trees on even well-kept grounds are starved ; but in a 

 different way. Instead of stone or cement there is a soil covering of sod, 

 kept in the best possible condition, frequently cut and rolled, while 

 the leaves that fall in the autumn are carefully removed and burned. 

 Where fertilizer is put upon the ground at all, there is usually only 

 enough for the sod, and the feeding grass roots are present in such 

 abundance that very little gets below them to the tree roots. Moisture 

 is absorbed in the same way, and frequently a tree suffers from 

 drought even if rain has fallen sufficient to keep the grass in good 

 condition. It is true that the feeding roots of trees extend down 

 deeply and that they obtain food and moisture far below points 

 accessible to grass roots, but in the course of years, if nothing is 

 added, the tree exhausts all available food and begins to suffer. This 

 is particularly true of those forest trees that have been left when 

 the original woodland was cut, and many an oak, hickory and chest- 

 nut is dying from starvation whose owner would pay heavily to save 

 it, did he only know how. 



From the entomological standpoint these matters are important, 

 because many insects do not attack trees until they show signs of 

 weakness, and that is especially true of borers. When a tree becomes 

 thoroughly infested by borers, there is little hope of saving it; the 

 thing is to prevent attack by keeping the trees in healthy, growing 

 condition. This applies generally, and one of the best methods of 

 preventing insect injury is to keep trees and shrubs in as thrifty a 

 condition as possible. See that there is abundant plant-food and 

 water available, and treat the trees as you would other living beings. 

 Plants have life — different in kind, perhaps, from that of animals — 

 but nevertheless a life that needs nourishment and favorable condi- 

 tions. Plants suffer from insect attack in almost all their parts, but 

 we have, generally, to deal only with those that injure either the 



