Monday, August 30, 2010

Dutch Elm Disease

Many summers ago, when I was young and much more energetic, I was trained by the Agriculture Department of the State of California to detect Dutch Elm Disease. Identifying Dutch Elm Disease was drilled into me, and I spent four months scouring bay area neighborhoods looking for trees with evidence of the disease. I can still identify all five types of elm trees, and am pretty good at ascertaining which elm trees might be ailing from Dutch Elm Disease.

I can spot an elm tree two blocks away. I can identify Dutch Elm Disease without a lab test. I was trained 30 years ago, and I am still as good as ever.

For the uninitiated, there is no such thing as a "Dutch Elm Tree". There are European Elms, American Elms, Chinese Elms, Japanese Elms and Silberian Elms, but no Dutch Elm Trees. Various types of elms trees have been planted in the Greater San Francisco Bay Area over the years, and there are a few in my Willow Glen neighborhood.

On my daily walk to downtown Willow Glen, on the corner of Lincoln and Pine, are two large stately European elm trees. One, leafless, is clearly dead; the other one is clearly ailing, the leaves at the crest of the tree brown and dry and curled, clear symptoms of the dreaded Dutch Elm Disease.

I ran into the neighbor who owns the two trees. He seemed sympathetic. The trees both need to be cut down before the disease spreads, via an elm beetle that flies from tree to tree.

Perhaps now, 30 years later, there are ways to treat Dutch Elm Disease. Unfortunately, a dead tree is still a dead tree. And dead elm wood is still dead elm wood. Unfortunately, guess where elm beetles like to breed?

So if you have an elm tree, keep it pruned to remove the dead wood. And if the leaves on your tree are turning brown prematurely, get an expert opinion as soon as possible. If you act quickly, you might not have to take the drastic step of cutting down your tree.

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