Tree alert: Dutch Elm Disease back in West Seattle, elsewhere

A tree alert just sent out by the city Transportation Department (SDOT) has some important info for West Seattle – read on to see the whole thing:

Dutch Elm Disease Re-emerges in Seattle
Residents should watch for elm trees bearing signs of disease

The Seattle Department of Transportation (SDOT) warns tree owners that Dutch elm disease (DED) has reemerged across the city. The department encourages citizens to be watchful and report the telltale signs of Dutch elm disease on trees located on public and private property. This is the typical season for the disease, which has already been found in the Seward Park, Kinnear Park, Maple Leaf and West Seattle areas. Trees citywide are being inspected and large elm trees will be removed from public property in several locations, as this is the only proven means of eliminating the disease.
Following Mayor Nickels’ policy, each tree removed on public property will be replaced with two trees.

Because DED is a fungus that invades an elm’s vascular system, causing the tree’s immune system to stop circulating water, the disease’s first symptoms are excessive wilting and/or drooping of leaves at the crown of the tree. The browning of the leaves usually starts at the tips of branches and works its way down the tree, and ultimately the tree dies.

SDOT’s Urban Forestry staff, led by City Arborist Nolan Rundquist, is available to inspect and test suspicious looking elm trees located within Seattle street rights-of-way. They will provide a visual evaluation of trees and limited prevention assistance on private property, but cannot do testing of private property trees. DED provides a harsh lesson when a favorite elm tree must be removed, so Rundquist asks residents to be diligent in looking for its symptoms. The Urban Forestry staff can be reached at 206-684-TREE (8733) or via e-mail at For additional information, please visit

The disease is often transmitted by the elm bark beetle, which feeds, breeds and nests in elm wood and comes in contact with the fungus. Tiny fungal spores are then carried on beetles to healthy elm trees, sometimes miles away. Root grafts can also cause the spread of DED, as can storage of elm wood for firewood that is inhabited by elm beetles, which is believed to be the way the disease first spread to Washington State in 1974. Rundquist notes that no elm wood should be stored for firewood unless the bark has been removed.


Dutch Elm Disease (DED) Information
During the summer of 2001, Dutch elm disease (DED) was first verified in the city of Seattle. Now that the summer of 2008 is here and DED has been found in several locations, the Urban Forestry professionals in city government are asking citizens to assist them with their efforts to control this disease.

Dutch elm disease (DED) is a potentially fatal disease that affects nearly every species of elm that grows in the Seattle area. Other tree species, such as maple or oak, are not affected by this disease. A fungus (Ophiostoma-ulmi), which is carried by a bark beetle, invades the water transporting tissues of elm trees, causing a chemical response by the tree. The tree’s water conducting tissues are blocked by this response, which results in the death of the tree

What is the City doing?
The Seattle Department of Transportation (SDOT) will provide inspection and laboratory testing of elm trees located on street rights-of-way, and will give limited assistance for disease identification for infected trees on private property. For more information, you may contact the City Arborist at 206-684-TREE (8733) or via email at

A brochure, which contains information about the disease, is available online at: You may also obtain a copy at most Neighborhood Service Centers, at Parks and Recreation Community Centers, and by request from the city arborist at (206) 684-TREE (8733) or via email

Seattle Department of Parks and Recreation has instituted an Integrated Pest Management (IPM) program designed to protect elm trees that are located on Parks property. This program includes preventative injection treatments and sanitation procedures for pruning and disposing of infected elm trees. For more information, you can contact Mark Mead, senior urban forester at 684-4113 or via e-mail at or Barb DeCaro, IPM coordinator, at 615-1660 or via e-mail at

What can you do?
Please do not have elms pruned between April 1 and October 1. Have dead branches removed from your trees in late fall or winter to limit the breeding habitat of the insect that carries the fungus from tree to tree. Do not store elm wood for firewood unless the bark has been removed.

Look for wilted or discolored leaves in the crown of the tree. If your tree doesn’t look normal, contact the city arborist at 206-684-TREE (8733).

If your tree is diagnosed with Dutch elm disease, it should be removed within ten days of diagnosis and disposed of properly, in order to limit the spread of the disease.

1 Reply to "Tree alert: Dutch Elm Disease back in West Seattle, elsewhere"

  • JumboJim August 26, 2008 (8:43 pm)

    Interesting article although I have to say I don’t see many elm trees around Seattle. As it is an ornamental, and not native, this should be restricted to street and landscape trees and not the urban “forest”. Its sad to lose any of our urban trees though – enough of them are falling to development.

    So Nickels plans on a two-for-one replacement? Maybe we can check back in a few years. The percentage of Seattle’s street tree cover has fallen quite a bit in the last 10+ years… The de-greening continues.

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