HINTS OF TREE SURGERY 223 



from decaying, will exclude insects and kill all which have succeeded 

 in securing an entrance. If there is soft rotten wood under the bark, 

 scrape out the cavity as clean as possible, removing all decayed wood. 

 A carpenter's gouge is a good tool for this purpose. Then paint the 

 inside of the cavity with coal tar which has been boiled not pine tar. 

 After drying, fill with Portland cement and smooth carefully around 

 the edges. This will arrest decay and the bark will grow over, pro- 

 viding the cavity is not too large, or may remain exposed and be 

 painted to resemble the bark color. 



