INJURIES TO SHADE-TREES 147 



however, as there are overhead telephone, electric -light, and 

 trolley-feed wires in cities, there will be interference with 

 trees, and it will require continuous watchfulness to reduce 

 the evil to a minimum. 



In the first place, it should not be permitted to attach 

 wires of any kind to trees on a public highway. Sometimes, 

 as in the case of the telephone, it is not the wire that does 

 the mischief, but the way it is attached to the tree. If rope 

 is used, it does not harm the tree. If wire is employed 

 instead, and is allowed to remain on the tree for a number 

 of years, it girdles the limb and kills it. Such cases are 

 very numerous. The wire is not noticed, and it is only 

 when a dead branch appears on the tree that the fatal wire 

 is discovered. Sometimes when the -central stem of a tree 

 is so girdled, the entire top dies and the tree is ruined. 

 Then, again, linemen, unless especially cautioned, use metal 

 spurs to climb trees, and great injury is likely to result to 

 the tree from such a practise. Sometimes a man's foot slips 

 and a deep gash is inflicted on the limb. 



Escaping Electrical Currents. Where wires pass through 

 trees, they should not be allowed to come in contact with 

 limbs, because their swaying causes an abrasion of the bark. 

 The continuous rubbing prevents the healing of the wound ; 

 in time the wood dries and checks, the limb decays, and 

 breaks in a storm. In fact, it has been found that all the ill 

 effects of wires running through trees are the result of 

 mechanical injuries followed by decay. The instances of 

 direct killing of trees because of escaping electricity are 

 very rare. It is during wet weather, when live wires touch 

 a tree, that there is a grounding of the electric current 

 through it. Frequently local damage results by the burning 

 of the part in contact with the wire or cable. 



