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 per- 

 manent success or failure of the operation; the work is still in 

 , „ an experimental stage. The car- 



m 



m 









160. 



A cement-filled cavity at the 

 base of a tree. 



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 subhmate, 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 



