- The Washington Times - Wednesday, August 17, 2005

Dutch elm disease is threatening hundreds of trees in the District, and volunteers and agencies are working to stop the fungus from spreading.

The disease has killed 116 trees, 106 of which were American elms, said Heather Whitlow, director of green infrastructure planning and design for the nonprofit Casey Trees Endowment Fund. American elms are found primarily in the District.

“Washington, like many other cities, uses the elm as a commonly planted tree,” said James Sherald, chief of natural resources and science for the National Park Service’s National Capital Area office. “It was a major concern because we didn’t want to lose all, or a large portion, of our street trees.”

A survey of city trees conducted from June 9 to July 2 found 426 of the District’s 10,336 elms carrying the disease, Miss Whitlow said. About 400 of the 8,411 American elms in the District are suspected to be carriers.

Several groups and agencies participated in the survey, including Casey Trees, the Park Service, the D.C. Department of Transportation’s Urban Forestry Administration and the U.S. Forest Service.

“This is something to be concerned about,” said Dan Smith, a spokesman for Casey Trees. “It’s not yet in full crisis mode, but it is something that needs to be taken seriously.”

Officials are not sure how long the infection has been active among city trees. Data from the survey are being assessed, Mr. Smith said.

“We just got preliminary numbers,” he said. “It’ll take a few more numbers … to come up with a more accurate picture of what were the causes, and what did occur.”

Dutch elm disease suffocates a tree’s roots, preventing them from absorbing water or nutrients. The disease is spread through elm bark beetles.

The Urban Forestry Administration will remove any tree found to be severely infected, officials said.

If a tree is slightly infected, it will be treated with a fungicide and sheared, Mr. Sherald said. When an elm dies, it is replaced almost immediately.

Dutch elm disease first took root in the United States in the 1930s, when a shipment of infected logs arrived in Cleveland from France, Mr. Smith said. Since then, the disease has been a widespread problem for communities where elms are plentiful.

“Villages throughout New England found that American elms really were the characters of their communities,” Mr. Smith said.

Since the 1930s, as many as 100 million elms have died nationwide from Dutch elm disease.

In 1959, 38,250 elms were reported in the District, which saw its first case of the disease in 1947. By 1993, the count had dropped to about 25,000.

In recent years, communities nationwide have begun planting a variety of the American elm that has a high tolerance to Dutch elm disease. The District has been at the forefront of the restoration.

Casey Trees announced its planting effort in the spring of 2003 and has planted 583 disease-tolerant Princeton American elms throughout the District.

The planting campaign followed an unprecedented inventory conducted by Casey Trees in the summer of 2002, when hundreds of volunteers identified and mapped 106,000 street trees in the District and 23,000 empty tree spaces.

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