CHAPTER VIII. 
FOREST PROTECTION. 
INJURIES TO TREES. 
The causes of injury to tree growth are many and various, 
some affecting principally the cultivated trees in windbreaks and 
shelterbelts, and others affecting the forest plantations and large 
areas of timber. Some injure or destroy the trees or tree seeds, 
and others do damage to the land on which they grow. 
Saw-Flies and Tent-Caterpillars. 
At present perhaps the 
most serious injuries to cultivated trees in this section result 
from the neglect to take precautions against leaf-eating insects. 
such as saw-flies and tent-caterpillars. 
Figure 22. Elm tree that has been 
planted five years and was pruned to 
a bare pole when set out. 
These injuries may be 
largely prevented by 
the use of Paris Green, 
in a liquid form, ap- 
plied by means of a 
force pump, using the 
solutions from a barrel 
carried in a wagon or 
on a stone boat. An 
ordinary spraying noz- 
zle should be used, 
with a sufficient Iength 
of hose to reach up 
into the tree. In order 
to reach the tops of the 
trees it may be neces- 
sary to have a raised 
platform on the wagon, 
and to attach the noz- 
zle to the end of a long 
bamboo pole. In most 
prairie groves this is 
practicable, but with very high trees it is very difficult if not 
entirely impracticable, 
