30 



Pruning. 



Attention should be given to the removal of all dead limbs on 

 shade trees and all wounds should be antiseptically treated with a 

 thick coat of paint or coal tar. 



Cavities. 



If there are cavities formed by decay in a tree which is of value 

 they should be carefully dug out, scraped and treated first with cre- 

 osote, and then with tar. If it is necessary to fill the cavity, Port- 

 land cement should be used, for the rough work employing grouting, 

 — one part cement to five of sand and gravel, — and for the surface 

 one part cement to two of sand. It is essential that the cavity 

 should be thoroughly treated and filled and all moisture prevented 

 from entering. If it is not desired to fill the cavity, it can remain 

 open or be closed over with tin. In no case of filling should the 

 cement extend beyond the wood. 



Chaining and Bolting. 



When trees show a tendency to split, they may be strengthened 

 by bolts and chains, but whichever are used, care should be taken 

 to have the work done thoroughly to prevent infection from fungi. 

 When bolts are put through the tree, they may be treated with tar 

 and the washers and nuts imbedded in tar and elastic cement, flush 

 with the wood. An extension bit is valuable for this purpose. 



Wires. 



To prevent injuries from electric wires, wooden or porcelain insul- 

 ators should be used to protect the trees. Wires should not be 

 allowed around trees in any form which would cause girdling. 



