CORVALLIS, Ore. – Even as lead of the Oregon Forest Pest Detector Program, Dan Stark missed the moment emerald ash borer breached Oregon’s borders.
“I went up to a concert for the first time since COVID,” he said, “I was out in the Sierra Nevada.”
He returned to the news: The dreaded invasive beetle — which had been making its way across America, leaving a path of damaged, dying and dead ash trees in its wake — had been found in Oregon. The Oregon Departments of Agriculture and Forestry and other agencies Stark worked with had been planning for years for its arrival.
“To then come back to the emerald ash borer detection, it was sobering,” said Stark, an assistant professor of practice who specializes in forest health and invasive species with Oregon State University Extension’s Forestry and Natural Resources program. “I knew it was on its way, and then it’s here.”
The beetle was first found in 2022, on ash trees bordering a school parking lot in Forest Grove, a small city 25 miles west of Portland. A coordinated response began immediately, including scouting, trapping, education, research, quarantines and other actions designed to “slow the spread.”
Stark spends a lot of his time thinking about how pests may affect Oregon’s forests. He is moved by the collaboration between agencies, institutions and concerned Oregonians. “It was really incredible to experience just how quickly this team activated and went right to work,” he said, referring to the Oregon EAB Readiness and Response Plan — developed and implemented by a team of collaborators, including OSU Extension.
“Things amped up quickly, the agencies got together, and this plan was deployed,” Stark said.
Oregon now faces the spread of the emerald ash borer, not only within Washington County but with recent detections in Marion, Yamhill and Clackamas counties. OSU Extension continues to engage Oregonians since more spread is expected, and forest health remains a high priority.
The plan is working
Stark explained that recent detections of the emerald ash borer signal that the response plan is working. It was always known that the distribution of the beetle would expand over time: more than 20 years of tracking the beetle across the United States demonstrated this.
A vital part of slowing that spread is knowing exactly where it is. The faster we find the beetles, the faster we can “start whatever work needs to be done in those areas to slow that spread,” Stark said. Interventions include tree removal, treatment with the chemical emamectin benzoate to protect ash trees, and the use of biological control agents, all of which are being tracked for research to inform future response plans.
To know exactly where the beetle is, you need to have as many eyes on the ground as possible.
That is where OSU Extension comes in, explained Lorelle Sherman, the Extension forester for Benton, Linn and Polk counties. “Because we have relationships with the community, OSU Extension has the foundation to effectively get information out,” said Sherman.
Even before the beetle was detected in Oregon, Extension shared information about what the beetle looked like and its effects on trees. Extension foresters held workshops for landowners and those specifically working in forests to teach them how to identify signs and symptoms of the wood-boring beetle through programs like the Master Woodland Managers and Oregon Forest Pest Detector.
They also worked on public awareness like educating campers not to move firewood — it could spread emerald ash borer and other invasive pests.
And this work paid off. A worker with Arbormetric, which contracts with Portland General Electric, had been trained this summer by State agencies on emerald ash borer detection. Just a few weeks later, he recognized the signs of emerald ash borer in an ash tree in Marion County and reported it to the Oregon Invasive Species Council hotline. “That is how you know that outreach has been effective,” said Stark.
A strong team
Extension has hired foresters from across the nation who can provide insights into the effects of emerald ash borer on various forests.
“I've just kind of lived all over the country and worked forestry jobs in a lot of different ecosystems,” said Sherman.
Fighting the emerald ash borer isn’t just professional for Sherman. It’s personal.
“I grew up in southwestern Pennsylvania, where the emerald ash borer really decimated a lot of the forest that I grew up hiking in,” Sherman said. As a college undergraduate, she volunteered with organizations that share information about the effects of the invasive species.
Jake Barker joined OSU Extension this summer as the forester for Columbia, Washington and Yamhill counties. He comes from supporting landowners in Connecticut who are “still dealing with the repercussions of the emerald ash borer. It’s much further along in terms of how it's progressed and impacted forests,” he said.
Barker is impressed with what he has seen since coming to the Pacific Northwest. “Oregon has a robust approach to invasive species monitoring, detection and response,” he said. He credits the collaboration between various entities: “It is a total team effort.”
He envisions the team extending to the general public.
“A really unique component to this situation is that it’s a threat to ash trees no matter where they are,” said Barker. “Forestry concerns are often split between urban forestry and rural forestry. This problem spans from urban to suburban to rural.”
“It gives us an opportunity to build responses and collaboration that spans that range,” he said. “It is also a chance for people to learn more about the trees and ecosystems around them, whether it is a grove of Oregon ash in a family forest or park, or a planted ash street tree in a city.” He encourages everyone to walk around a local park or nature preserve and try to identify an ash tree. (Extension has an easy guide.)
Envisioning a low-ash future
The reality of the emerald ash borer is that eventually most ash trees will die. Researchers have tracked the spread of the beetle across the United States for over 20 years and the trend of almost complete loss of ash trees to beetle-kill remains the same.
While “slow the spread” efforts help contain the beetle, researchers are looking towards a future where ash trees will have to be replaced with other species.
“It’s really going to be a case-by-case basis,” said Sherman. “Oregon ash grows in a range of soil types in western Oregon. Landowners will have to pick and choose what might be best as a replacement species for their property based on a spectrum of environmental variables.”
The research has been consolidated in an Extension publication.
While Oregon ash isn’t grown commercially for timber, it is an important tree in wetland and river ecosystems. It’s able to grow close enough to shore to shade the habitat. Planting suitable replacements is vital for not just forest health, but wetland health, too. Other species of ash are also commonly planted in yards, parks, and along streets across the state.
A long-term perspective helps in planning for new forests, which may look different not just due to the loss of ash but to effects on other species.
“Our forests are constantly in a state of change. A species may die, giving way to new species. While it looks like a grim outcome, there will inevitably be a shift to a new ecosystem,” said Sherman.
She tries to view it as an opportunity.
“It doesn’t have to be all negative,” she said. “We can be hopeful.”
