Foresters are taking down danger trees

Eighty-six "danger trees" have been identified between Pine Street in Sisters and the turnoff from Highway 20 to Jack Lake 16 miles to the west. They have been targeted for immediate removal. The trees are dead or dying and at risk of falling onto the highway.

Removal operations are underway and are expected to be completed this week. There may be traffic delays.

Wood will likely be left in place for the season.

The remainder of the dead and dying trees - well over a thousand - will be felled in spring.

A growth-regulating herbicide produced by Du Pont, and sold under the brand name Perspective®, appears to be the cause of the significant death of ponderosa pines along the Highway 20 corridor northwest of Sisters.

At a meeting held on Monday, September 24, to inform the public about the proposed Highway 20 Corridor Public Safety Project outside Sisters, representatives of the U.S. Forest Service, Oregon Department of Transportation, and Oregon Department of Agriculture provided background information and answered questions from the public.

In total, there are over 1,450 trees that have been identified as exhibiting symptoms associated with herbicide injury. Removal of those trees will be undertaken in a separate project in the spring.

In 2012/13, ODOT contracted with knowledgeable retired Jefferson County weed specialists to apply herbicidal treatment to the US 20 right-of-way (ROW) to prevent vegetation from growing on the road shoulder, in order to maintain the road ditch allowing the road to drain properly.

In addition to providing for drainage, the vegetation removal reduces the risk of fire from automobile sparks or cigarettes, improves roadside visibility, and reduces the spread of invasive weeds. There were a number of factors in play when Perspective® was chosen.

Because ODOT sprays thousands of miles of right-of-way every year, they had a directive to reduce chemical use. The growth-regulating herbicide Perspective, formulated by DuPont, had just been approved in January 2011. It was touted as being more effective while using less chemical, therefore reducing poundage of chemical applied per acre. It appeared to be a problem-solver. This was one factor influencing the selection of this product.

However, it turns out that conifers in nine Midwest states had been damaged or killed by another Du Pont product, Imprelis, containing the same active ingredient as Perspective. In that part of the country, the Norway spruce and white pine were the most susceptible to harm from aminocyclopyrachlor. Imprelis was ordered off the market after the Environmental Protection Agency received more than 7,000 reports of damaged or killed trees throughout the Midwest.

According to a December 2015 Facilitated Learning Analysis provided by Ian Reid, Sisters District Ranger, "The use of Perspective was not a violation of the label because label language was cautionary rather than mandatory. The label caution says do not spray where conifers may be affected, unless loss can be tolerated. Because loss tolerance is a judgment call, this language is not considered a mandatory restriction."

The analysis went on to say that root contact might have been an exposure mechanism. "Great care was taken to apply the products so that they stayed in the immediate road shoulder. However, root contact as a mechanism of transfer may not have been fully appreciated."

Other local environmental factors and stressors may have had an impact.

"This product may behave differently in this area than in other locations that are drier or are less forested," the analysis states. "Many stressors were considered in the dieback of these trees including drought, exhaust, and salts. Diagnostic indicators of herbicide damage such as swelling on recent growth of shoots or callus tissue and the curling of new shoots (epinasty) are evident."

Another issue discussed at the September 24 meeting had to do with turnover in key personnel and resulting communication failures.

"Several key players retired or moved during the 2012-2015 period. This decreased or eliminated coordination and affected communication on the issue," according to the analysis.

ODOT has a memorandum of understanding (MOU) with the USFS for maintenance and operation of highways through National Forest lands. That MOU includes application of herbicides along highway ROWs. According to Reid, the USFS "will continue to implement the state-wide MOU. Locally, the Deschutes NF and ODOT can add to the MOU by a more thorough review of proposed herbicide use. Local leadership from both agencies can document that they have reviewed and discussed any use of an herbicide before its application."

According to Dale Mitchell, Pesticides Program Manager for the Oregon Department of Agriculture, "ODA would recommend USFS also open communication with U.S. EPA (Environmental Protection Agency) as an additional resource on national pesticide incident reporting information associated with pesticide active ingredients that are being considered for use on federal lands. As federal partners, communication between federal natural resource agencies on a national level may prevent future incidents and refine the selection of appropriate tools for pest control."

Mitchell reported that the Oregon Department of Agriculture has enacted a temporary rule prohibiting the use of any pesticide product containing the active ingredient aminocyclopyrachlor on ROW sites.

"Based on current information, there are at least four locations in Central Oregon where ponderosa pine, lodgepole pine, and possibly other valuable tree species appear to have been negatively impacted by the herbicide aminocyclopyrachlor, which was applied to certain ROW sites," DODA states. "Trees in some previously treated areas continue to decline, and the USFS has identified 1,454 dead or dying trees along Highway 20 near Sisters. Some of these trees are old-growth ponderosa pines that are 150-300 years old. These measures are being taken in an abundance of caution to protect Oregon's natural resources."

Tree removal along Highway 20 comes with a big price tag.

"We are still working out the cost-sharing of the project between ODOT and the FS," said Reid. "Our initial estimates for project costs (not including traffic control, which ODOT would be responsible for) are $250,000 to $350,000. This includes service contract, personnel costs for implementation and planning, fleet, equipment, and supplies."

The wide range of the cost has to do with how the trees in the spring are eventually handled - whether they are all felled or some topped. Topping is more expensive than felling the entire tree.

The Forest Service hopes to be able to complete the spring project in April before nesting season. The pace and timing of the project will be dependent on the weather and soil saturation. There can't be any snow or ice on the highway at the time of the two-to-three-week project.