August 
19 22 
53 
The story of this elm is characteristic of many large old trees. The inroads of wind, rain 
and ice, followed by insects and fungous diseases, threatened its life. To save it the decay 
was removed, the trunk braced and the cavity filled to prevent a recurrence of its weakness. 
Illustrations by courtesy of the Davey Tree Expert Co. 
OPERA TING ON TREES 
The Ills and Injuries Made by Pests , the Elements and Man 
Often Require Drastic Surgery 
O NE of the principal, but not neces¬ 
sarily the most important, operations 
in the care of trees is the treatment of 
cavities in their roots, stems and branches 
in a manner much like that which a dentist 
employs in taking care of a cavity in a 
tooth. It is possibly this phase of the treat¬ 
ment that gets the most abuse, and about 
which the tree owners desire and need the 
most information. 
Cavities develop indirectly, because of 
wounds in the protective bark-covering of 
the tree. The insect pests and fungous dis¬ 
eases find these wounds and immediately 
start destruction. It may be six months or 
even a period of a year or more before the 
cavity is well started, but it always comes. 
And, because of the nature of a tree’s 
growth, a cavity once started cannot be 
healed without the assistance of skilled hu¬ 
man hands. It may become covered over 
on the outside but it never heals, and most 
of us know what happens to ourselves when 
the skin heals over a wound before the in¬ 
fection has been removed from beneath. 
The causes of wounds on trees are almost 
infinite, so numerous in fact that only a 
JOHN DAVEY 
few of the more important ones can be men¬ 
tioned in this brief article. One of the most 
serious is the many storms which sweep over 
the country. Those of last November in 
New England, of March in Wisconsin and 
Michigan and of June in New York are so 
well remembered that little more need be 
said. Branches are torn from the trunks, 
and sometimes the roots even are torn 
asunder and the giants are hurled to the 
ground. Lightning, too, does its damage in 
many ways. 
Many of the insects which cause so much 
havoc after the wounds are made have also 
the facilities for making their own wounds. 
These cannot be better illustrated than by 
the various borers, especially those which 
are killing our hickories and white birches 
throughout the county. 
Last, but far from least, is man’s own 
carelessness and ignorance. Lawn mowers, 
automobiles, wagons and many other man- 
controlled machines take their yearly toll 
of trees because of the wounds which they 
have made in years gone by. But all of 
these together do not take any greater toll 
than does pruning which is done improperly. 
Almost fifty per cent of the cavities in trees 
result from improper pruning. Branches 
are cut off too far from the parent stem, 
leaving a stub which absolutely cannot 
heal; or they may be cut too close, leaving 
a larger wound than necessary, which will 
certainly decay before it can possibly be 
covered by the new growth. 
Still other trees are structurally weak and 
split almost from their own weight. These 
are known as crotched trees; and with them 
we are becoming more familiar every day. 
Water freezing in the crotch during the win¬ 
ter exerts a tremendous pressure which rup¬ 
tures some of the fibers. A yearly repeti¬ 
tion of this soon produces a cavity that, 
without skilled treatment, means destruc¬ 
tion. 
Several times skilled treatment has been 
mentioned and now let us consider what 
constitutes skilled treatment. Probably all 
of my readers have had dental work done, 
and it may be just possible that some of 
them have had cavities filled when a small 
bit of decay had escaped the dentist’s eye. 
What followed was a sad experience. In a 
(Continued on page 86) 
