No. 98: Mar-Apr 1995
In 1986, the U.S. Navy began operating a 90-kilometer-long radio antenna stretching pole-to-pole through a Michigan forest. Broadcasting at only 76 hertz, this long antenna can communicate effectively with submerged submarines. Although the antenna produces electromagnetic fields about the same as those from a large household appliance, some of the trees adjacent to the antenna have enjoyed an unexpected spurt in growth, according to D. Reed and G. Mroz of the Michigan Technological University.
"The researchers have been gathering data on the growth of trees since 1985, making measurements at two sites, one near the antenna and the other 50 kilometers away. The results seem to suggest that the electromagnetic field has a subtle influence on the forest. They found that two species of trees, northern red oak and paper birch, do not seem to be influenced by the antenna at all. But red pines near the antenna grew taller than red pines at the distant site, while aspen and red maple grew thicker than their counterparts further off."
(Kiernan, Vincent; "Forest Grows Tall on Radio Waves," New Scientist, p. 5, January 14, 1995)
Trees are not the only plants affected. Algae in the upper Ford River, where the field is only 10% as strong as that near the antenna, increased chlorophyll production sharply after the antenna started operation. The cause of the growth spurts in trees and algae is still a mystery.
(Holden, Constance; "EMF Good for Trees?" Science, 267:451, 1995.)
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