BEND, Ore. (AP) — A weed-killer that killed thousands of ponderosa pines near Sisters has been linked to the deaths of other trees outside the Sunriver resort community and possibly across Oregon.
An investigation spurred by the incident in Sisters found that the active ingredient in the product known as Perspective may have killed dozens of ponderosa pines outside Sunriver and other trees in central Oregon, said Dale Mitchell, an Oregon Department of Agriculture program manager. The department monitors pesticides and herbicides in Oregon.
“We are looking at gathering additional information on this ingredient,” Mitchell said.
The Deschutes County Road Department sprayed the herbicide along two main roads that lead in and out of Sunriver in 2013 and 2014, the Bulletin reported. The roadside spraying is done to reduce the amount of flammable grass, said Chris Doty, the road department’s director.
Employees for the road department and the U.S. Forest Service found ponderosa pines with brown and ill-formed needles in the area where the herbicide was applied and reported it to the agriculture department.
Results from testing in 2015 showed that the damage had spread, according to a U.S. Forest Service report.
Although it’s not confirmed if the herbicide caused the damage, Doty said some of the tree deaths and damage were the result of root damage or other unrelated issues.
In any case, the damage was much less than in the Sisters incident.
The active ingredient in Perspective, aminocyclopyrachlor, has been linked to deaths of thousands of spruce and pines trees outside of Oregon, according to The New York Times.
Tree damage was also reported in other parts of Deschutes County after Perspective was applied near several roads. But Jean Nelson-Dean, public affairs officer for the Deschutes National Forest, said research shows the damage could have been caused by mountain pine beetles.
The Oregon Department of Agriculture has notified the U.S. Environmental Protection Agency of the situation. The offices are discussing the possibility of strengthening the language on the label for Perspective.
The county has discontinued its use of Perspective, Doty said.