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Injuries to Trees From Electric Wires

The damage done to roadside trees offsets to an alarming degree the benefits derived by the public from the telephone and the trolley. The poles are set in the line of the trees, and the wires threaded between them. The limbs that might strike the wire when the wind is high are hacked off. Miles of road are lined with trees ruthlessly beheaded and utterly ruined under the direction of the foreman in charge of the pole setting. The workmen proceed rapidly through a section of country, passing from one property to another. They keep an eye out for objections; the owners could make them a great deal of trouble. But rarely is there concerted action, unless it be a mass meeting to bewail the damage after it is done. Then things settle down, and the poor maimed trees do their best to heal their wounds and to grow new tops. As they reach up they encounter the wires, and this interferes with the service. The offending trees are shorn again. They finally become stunted old pollards, throwing up groves of straight water sprouts, year by year, if they are by nature inclined to sprout from stubs.

"Burns" that cost the lives of large limbs are proved to result from contact with electric wires passing through treetops. Proofs are also indubitable that trees are killed by the same cause. Investigations made by the Experiment Station of the Massachusetts Agricultural College in 1903 led to the following conclusions (Bulletin No. 91):

1. The high resistance offered by trees serves as a protection against death from an electrical contact. (Wood is a non-conductor when dry, but when wet it is a partial conductor. After a rain one often sees sparks in trees caused by electric wires that touch the branches.)

2. There are cases where the direct current, used in operating street railways, has killed large shade trees.

3. Electrical currents act as stimulants to growth up to a certain degree of intensity. Beyond that degree, growth is retarded, and the death current is the maximum.

4. The greatest damage caused by alternating and direct currents is by local burnings. The stronger the voltage the greater the injury.

5. There is practically little or no leakage from wires during dry weather. In wet weather a film of water covers the tree and leakage is likely to occur. If insulation is defective and contact between wire and tree exists, grounding results, and the tree is burned where the wire touches it.

6. While no instance has shown death produced by alternating current, yet the proofs are absolute that this cause maims and disfigures young trees so badly that it amounts to their destruction.

7. Arc lights in close proximity to trees cannot be discovered to be accountable for any sickliness these trees exhibit. Poverty of the soil, paving, etc., are generally the causes.