PROTECTION OF SHADE TREES FROM MUTILATION. 343 



large trees netting fastened on the street side will usually be 

 sufficient. 



Mutilation by unskillful trimming. When the limbs of a 

 tree are amputated, extreme care should be taken to make the 

 cuts close to, and perfectly even with, the trunk. If the pruning 

 is done in this manner, the wounds heal more quickly than if 

 stubs of the branches remain, and after healing there are no 

 unsightly bulges at the point of cutting. Care should further 

 be taken that no bark is torn from the trunk, as often occurs 

 when a heavy branch is removed. In order to avoid this evil, a 

 cut should first be made on the under side of the branch at a 

 distance of a foot or more from the trunk, and then the branch 

 should be cut off just above the notch. The stub can then be 

 safely removed and a perfectly smooth cut made. 



After the removal of a branch the wound should be painted 

 with a coat of coal tar.* The painting of wounds of living 

 branches may be done best after the activity of the sap has 

 ceased, for at this season the coal tar will adhere most perfectly 

 to the wood. 



The trimming of dead limbs may be carried on at any season 

 of the year, but extensive pruning of living branches should 

 preferably be done when the trees are not in sap, for it has been 

 shown by experiments that wounds made in the fall and winter 

 tend to resist decay better than those made during the period 

 of growth.* 



No recommendations can be made regarding the trimming 

 of trees to improve the shape of their crowns, for this operation 

 can only be carried out by a skilled forester or landscape gar- 

 dener, who must treat each tree according to its individual 

 requirements. 



Mutilation by Wind Storms. Nothing can be done to protect 

 our trees against the wind other than to keep them in as strong 

 and thrifty condition as may be, thus giving them greater power 

 of resistance. 



5. Poisoning 'by Illuminating Gas. We have nothing at 

 present to recommend other than that the police should report 

 at once any suspected leakage of gas in the streets, both to the 

 Board of Public Works and to the Gas Company, and that the 

 latter should be required by the Board of Public Works at once 

 to examine and repair if necessary. 



* See note on page 351. 



