Treatment of Street Trees 117 
damage, systematic warfare should be waged against these 
pests, the means of which are discussed in the next chapter. 
In street trees the opportunity for mutilation is so great 
and the neglect so usual, that the tree surgeon will often be 
called upon to exercise his knowledge and ingenuity in the 
direction of mending old damage. 
Walking along the streets of any city one will find from 
at least twenty-five to fifty per cent. of the trees in a dam- 
aged condition. Tvhe principal cause of such damage is 
probably the gnawing of horses and the careless treatment 
of passers-by. The climbing irons of wire stringers and of 
careless tree-pruners also frequently lead to abrasions of 
the bark. Guy ropes attached to trees in building opera- 
tions are a frequent cause of damage, unless properly pro- 
tected by boards in such a manner as to properly distribute 
the pressure and prevent laceration and bruising of the 
bark. The piling of stones against the base of trees with- 
out protection is also apt to result in bruises. 
The proper thing, of course, is to abstain entirely from 
such use of trees. But since the casual damage done can 
hardly be avoided by regulations, young trees, at least, 
should be protected by suitable guards, until their bark 
has become robust and less likely to become damaged. 
The accompanying illustrations, showing a variety of 
guards as used in various cities of Europe and the United 
States, have been borrowed from a Bulletin of Cornell 
University Agricultural Experiment Station,’ and are self- 
explanatory. 
The following remarks on these protecting devices are 
taken from the same Bulletin. 
“The most primitive guard in use is a handful of branches 
1 “Shade Trees” by W A Murmill, Bulletin 205, Cornell University 
Agricultural Experiment Station, Ithaca, N Y, 1902 
