Elm Street Blues
A HERITAGE PRESERVED Since 1930, more than half of America’s splendid elm trees have succumbed to disease. But science is now fighting back and gaining ground.
October/November 1986 | Volume 37, Issue 6
They left behind great names —the Divine Elm, the Justice Elm, the Pride of the State, the Green Tree. In their dappled shade countless towns found repose, places like Elmhurst, Illinois; Elm Grove, Wisconsin; and New Haven, Connecticut, “City of Elms.” The trees carried the names of American heroes: the William Penn Treaty Elm, the Washington Elm, the Lincoln Elm. Under trees such as these, revolutions were pledged, treaties signed, oaths of office taken. But during the last fifty years, America’s big elms have disappeared, victims of Dutch elm disease.
One of the diseases to which elms are prone changed the way America looks.
To know why America loved and planted the elm, starting as early as 1646, one had only to walk under the soaring cathedral naves the trees formed. Helen Butler, a native of Syracuse, New York, remembers when that city, in the 1950s, was covered by one-hundred-year-old elms. “Oxford Street I can always remember. The elms made archways over the street and the sun would shine through and on a day that was very bright, especially in the fall when the leaves were beginning to turn yellow, it was almost golden going through the street. Just to look down it, just like gold.”
The elm is a storybook tree. “A great green cloud swelling on the horizon,” was how Oliver Wendell Holmes described it in The Autocrat of the Breakfast-Table . Thoreau in his journals thought the tree more noble than those who lived under it. The mature American elm ( Ulmus americana ) in its celebrated vase form, rises a hundred feet or so straight up, arching out to offer a dappled shade. The elm’s widely spaced leaves cast shifting shadows that admit enough light to allow a lawn to flourish and enough shade to cover half an acre.
The American elm, one of more than forty species of the tree, can stand the stress of a city environment. It has a wider range than any other American tree. An estimated seventy-seven million elms gave the nation’s towns and cities their characteristic look. But as a 1971 handbook for the U.S. Forest Service says, the elm “has a notorious pathology.” The handbook goes on to describe some fifty ailments, root rots, leaf wilts, stem cankers, bacterial wetwood, and various viruses and fungi. It was one of these diseases—Dutch elm disease—that changed the way America looks.
Dutch elm disease was first noticed in Holland in 1919. It spread through Europe and arrived in America in 1930 in logs imported for elm veneer. The disease is caused by a fungus that blocks the circulation of water and nutrients in elms, causing leaves to wilt and die. It is spread primarily by two beetles, one a native and one the devastatingly successful European bark beetle. Typically, the beetles, carrying spores of the fungus on their bodies, bore into a dead tree, breed there, and lay their eggs. In time the larvae mature and move on to a healthy elm to feed, carrying microscopic spores of the fungus with them. Having infected the healthy tree, they then return to a dying or dead one to lay their eggs and complete their life cycle. When the trees are set close together, as in cities, the disease can also spread through the roots.
The disease moved across the country like a wave, wiping out elms halfway across the continent before scientists began to understand how to control it. In 1933 the epidemic started out from the Atlantic ports of New York, New Jersey, and Connecticut. The first attempts to control the disease actually accelerated its spread by creating perfect breeding conditions for the beetles. WPA workers would pile up dead elm logs, or trees would be killed with copper sulfate and left standing, creating more deadwood. The idea was to set up a barrier, much like a firebreak, that the disease could not cross: experts believed the carrier beetles could not fly more than five hundred feet. It also was believed that by burning a dead elm, and thus destroying the beetles in its bark, adjacent trees would be made safe. Actually, the disease would have already beeri transmitted by then. As Dr. Gerald Lanier, professor of forest entomology at the State University of New York College of Environmental Science and Forestry in Syracuse, New York, tells it, the various misconceptions about the disease and the agility of the beetles that spread it were not finally resolved until the 1970s.
The country’s entry into World War II halted all efforts at control. By 1945 the disease had spread as far north as southern Quebec in Canada and as far south as Kentucky.
After the war the gray skeletons of elms were a familiar sight in numerous towns, and many people believed that all elms were doomed. There was no national program, but local groups who sought advice from the federal government were advised to spray their trees twice with DDT, at ninety-day intervals, as well as cleaning up deadwood. In the 1950s the epidemic continued to spread, reaching Kansas by 1957. To many Midwestern towns facing the death of their elms, DDT was a “miracle chemical.” It had been widely used in the war, and now, prescribed by the Department of Agriculture, it looked like the answer to their problem.