STEEET TREES. 45 



TREATMENT OF CAVITIES. 



1. Remove as much of the decayed wood as the location of 

 the cavity and the condition of the tree seems to warrant; 

 aim to expose a smooth surface of sound wood at all points. 



2. Sterilize the surface by a brush application of copper 

 sulphate or creosote. 



3. Give the cavity at least three coats of coal tar, avoiding 

 covering the cambium. 



4. If the cavity is of such shape that it will catch and 

 retain water, or if it is so large that the tree is weakened 

 thereby, fill it as directed below. 



5. If the cavity does not fall in either of the above classes 

 it is best to allow the natural growth of wood to gradually 

 cover over the defect. 



