Oregon targets black walnut disease in Salem
<p>Workers from R&R Tree Service remove a black walnut tree infected with thousand canker disease on the North Campus of the Oregon State Hospital in Salem, Oregon., on Monday. The company will be removing 14 infected trees.</p>
SALEM, Ore. (AP) - Crews are cutting down 14 century-old black walnut trees at the Oregon State Hospital and are trying to save 38 more from an infestation that could threaten the species citywide.
The infestation is called thousand cankers disease. It has broken out several times in the West since 2008 when it killed hundreds of trees in Boulder, Colo.
It's caused by a fungus and spread by tiny twig beetles native to the Southwest that live on the Arizona walnut, which isn't affected.
It kills by causing cankers around every spot where the beetles attack. The cankers expand, girdling and killing branches.
Experts believe people spread the disease by taking the wood state to state for lumber or firewood.
Workers from a Salem contractor went to work at the mental hospital Monday on 14 trees considered too far gone to save, the Statesman Journal reported.
"They were deemed to be diseased to the point they were dangerous there was so much dead wood," said Amy Williams, spokeswoman for the Oregon Department of Administrative Services.
Another 38 black walnuts on the campus are infected but are being pruned to save them as long as possible.
The Salem outbreak is the city's first. Others in recent years have been reported in California, Oregon, Idaho and Utah.
Some East Coast states have quarantined imports of black walnut from Western states, said Gary McAninch of the state Department of Agriculture.
"Either black walnut is totally prohibited or it has to be treated in such a way the disease and insect vectors are no longer present," he said.