164 THE BOOK OF FORESTRY 
tree to be moved the better the result in some Cases 
large trees ten to twelve inches in diameter must be 
planted along an avenue or in a park to give immediate 
results. In such cases the ground is dug away from 
the roots with great care, leaving a ball of earth and 
roots eight to ten feet in diameter. This tree is then 
carried on a specially constructed truck to its new 
position, where a larger hole partially filled with rich 
loam has been prepared. By root pruning these trees 
a year or two before they are to be transplanted much 
better results may be obtained. 
The general care and upkeep of the city’s trees of 
course are his concern. Trees must be sprayed with 
poisonous solutions to kill the army of leaf-eating in- 
sects which may consume all the leaves of a large tree 
in a short time. So serious have become the attacks of 
some of these pests that many cities have purchased 
high-power spraying trucks which will throw a fine 
spray of the poisonous material to the tops of the high- 
est trees. Such measures are necessary not alone on 
account of the unsightly appearance of the leafless tree 
but also because several such attacks will kill the most 
vigorous specimens. Throughout New England count- 
less elms are killed each year by the attack of the elm 
leaf beetle, while the presence of the imported moths 
in Massachusetts makes it necessary to spray large 
areas of wood land. 
Tree Surgery.—The pruning of trees and the filling 
of cavities, often spoken of as tree surgery, are phases 
of city forestry which need expert knowledge. Far too 
much of this work has been done in our American cities 
by men whose only qualification was assurance. The 
result has been tree butchery plus a large bill for 
services rendered. The proper pruning of trees requires 
