INSECT ENEMIES OF EASTERN FORESTS Pal | 
sections of the country, and even for a particular site or location, 
cannot be overemphasized. Some factors to take into consideration 
are adaptability to climate, rate of growth, size, form, longevity, soil 
requirements, root characteristics, “and susceptibility to insects or 
diseases. Many trees are so weakened by improper planting that they 
succumb readily to attack by borers. The usual planting instructions 
for various types of plants should be rigidly followed. In the care 
of trees consideration must be given to such factors as s pruning, effect 
of light, care of wounds, tree surgery, bracing, ee watering, 
and grading. Thorough consideration of these features can be ob- 
tained by consulting State or local authorities or by referring to 
Collins (107), Houser (239), Mulford (3177), Marshall (297), and 
Pirone (353). 
MUNICIPAL CONTROL OF INSECTS 
It is becoming the practice in most large cities to employ a force 
of trained experts to take care of the city trees. With such an organi- 
zation it is possible to keep on hand the expensive equipment needed 
for spraying, transplanting, pruning, tree surgery, and other neces- 
sary activities in prolonging the life and improving the epee 
of the trees. Even in towns with populations as small as 10,000 it 
would probably be economical in the long run to provide for compe- 
tent care of the trees and to purchase the necessary equipment. 
SELECTION OF TREES FOR ORNAMENTAL PURPOSES 
The old adage ‘tan ounce of prevention is worth a pound of cure” 
is particularly applicable in the case of shade trees for ornamental 
plantings. It is usually possible to select species well adapted to any 
particular locality or site and least subject to insect attack. In gen- 
eral, the conditions under which particular species of trees grow ‘best 
in nature should be given consideration when tr ansplanting “them for 
ornamental purposes. For example, the American elm usually 
grows on low ground, or at least where there is an adequate moisture 
supply, and does poorly on dry ridges or poor soils. In general, 
conifers, particularly pines, will do better on poor soils that are lack- 
ing in humus than will the hardwoods. Many States employ special- 
ists who can give advice on the best trees for a particular locality, 
and such authorities should be consulted. 
GRADING AND FILLING 
Changing the soil level about trees is a frequent source of injury 
leading to borer attack and the ultimate death of the tree. Scraping 
off the topsoil increases the temperature of the soil about the roots 
and actually kills many of them. Filling in with earth prevents 
passage of air to the rootlets and suffocates the plant. Where it is 
necessary to lower the grade about a tree, applications of manure 
or fertilizer should be made, particularly a mulch, when the topsoil 
is removed. If filling is necessary, a well should be built around the 
trunk of the tree with a diameter at least 3 feet larger than the 
diameter of the tree. 
FERTILIZERS 
The thriftier the tree, the less likely it is to be seriously injured 
by insects. Thrifty, healthy trees fully recover from attack by deto- 
liators more often than do poorly growing trees. Unhealthy trees or 
