146 MANUAL OF GARDENING 
“Tree surgery includes the intelligent protection of all me- 
chanical injuries and cavities. Pruning requires a previous in- 
timate knowledge of the habits of growth of trees; surgery, on 
the other hand, requires in addition a knowledge of the best 
methods for making cavities air-tight and preventing decay. 
The filling of cavities in trees has not been practiced sufficiently 
long to warrant making a definite statement as to the pcr- 
manent success or failure of the operation; the work is still in 
an experimental stage. The car- 
ing for cavities in trees must be 
urged as the only means of pre- 
serving affected specimens, and 
the preservation of many noble 
specimens has been at least tem- 
porarily assured through the 
efforts of those practicing this 
kind of work. 
“Successful operation de- 
pends on two important fac- 
tors: first, that all decayed 
parts of the cavity be wholly removed and the exposed sur- 
face thoroughly washed with an antiseptic; second, that the 
cavity, when filled, must be air tight and hermetically sealed 
if possible. Trees are treated as follows: The cavity is 
thoroughly cleaned by removing all decayed wood and wash- 
ing the interior surface with a solution of copper sulfate and 
lime, in order to destroy any fungi that may remain. The 
edges of the cavity are cut smooth in order to allow free growth 
of the cambium after the cavity is filled. Any antiseptic, such 
as corrosive sublimate, creosote, or even paint, may answer the 
purpose; creosote, however, possesses the most penetrating 
powers of any. The method of filling the cavities depends to a 
great extent on their size and form. Very large cavities with 
great openings are generally bricked on the outside, over the 
160. A cement-filled cavity at the 
base of a tree. 
