Devastating Tree Kill Along Highway 20

You may have read in The Bulletin or The Nugget that many dying trees along Highway 20 between Sisters and Black Butte are planned to be cut down because they were sprayed with a deadly herbicide over the course of three consecutive years. More than 100 of the iconic, old-growth ponderosa pine trees (some probably as old as this nation) which greet us when we arrive back into Central Oregon from Santiam Pass or the Metolius River Basin were killed.

There is much more to the story than what the various agencies said in the news articles. These aren’t just any trees, but trees that the public had earlier saved, and the killing of the trees was easily avoidable.  Contrary to the suggestion in the articles, it was well known that this herbicide harmed ponderosa pine trees.

As longtime defenders of the scenic and ecological resources of the forest, LandWatch is deeply troubled by the negligence that led to these trees' deaths. Join us in giving feedback to the Forest Service by May 29th. Read our letter here.

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Several years before the herbicide that killed the trees was applied, the Oregon Department of Transportation (ODOT) proposed a widening of Highway 20 from two lanes to four lanes. Many members of the public, including LandWatch, opposed this plan because it was unlikely to increase safety and would have resulted in the removal of many of the iconic, old-growth ponderosa pine trees along this scenic highway corridor.

After public outcry against the unnecessary highway widening project, including a 4-1 vote to oppose the project and save the trees by the Sisters City Council, the project was scaled back. Many of the poisoned trees are the same trees that the public fought to save.

ODOT and the Sisters Ranger District either knew or should have known that use of the herbicide would be harmful to ponderosa pine trees. The initial U.S. EPA product label for the herbicide, which was registered by the EPA on January 20, 2011, includes a section labeled “IMPORTANT PRECAUTIONS” that contains the following warning:

"Injury to or loss of desirable trees or other plants may result if equipment is drained or flushed on or near these trees or plants, or on areas where their roots may extend, or in locations where the chemical may be washed or moved into contact with their roots."
In 2012, the EPA product label was updated to include a new warning that specifically identifies ponderosa pine trees as a tree species that is particularly sensitive to the harmful effects of the herbicide:
“Certain species may, in particular, be sensitive to low levels of Perspective® Herbicide including but not limited to, conifers (such as Douglas fir, Norway spruce, ponderosa pine and white pine), deciduous trees (such as aspen, Chinese tallow, cottonwood, honey locust, magnolia, poplar species, redbud, silver maple, and willow species), and ornamental shrubs (such as arborvitae, burning bush, crape myrtle, forsythia, hydrangea, ice plant, magnolia, purple plum and yew).”

Despite these warnings, and despite multiple Forest Service land management policies for protecting this specific area, and the Metolius/Black Butte old growth, the harmful herbicide was sprayed along the Highway 20 corridor in 2013, 2014, and 2015. The result of this carelessness is a corridor of dead and dying old-growth ponderosa pine trees that the Forest Service wants to cut down.


The trees that were sprayed are now dead, but some of their character can be retained and the public can weigh in on the project by May 29th by writing to the Sisters Ranger District at with the subject line “Highway 20 Corridor Public Safety Project.”

We are asking for appropriate mitigation and corrective actions for the carelessness of the Sisters Ranger District and ODOT that resulted in harm to the old-growth ponderosa pine trees including, for example:

  • The old growth trees should not be cut down and removed. Instead, they should be "topped" by cutting or blasting so that they become wildlife snags and scenic boles of the trees with the distinctive bark are retained along the highway. That also removes the danger of trees falling on the highway.
  • An investigation should be done to find out how this happened in order to figure out how to prevent this from occurring again.
  • Public notice and comment should be required on any future herbicide use in scenic corridors and in the Metolius Conservation Area.