The beetle is coming for Oregon Ash trees, but scientists and residents can help soften the blow.
Just outside Cottage Grove at the U.S. Department of Agriculture’s Dorena Research Center, scientists are playing a numbers game: They’re growing thousands of Oregon Ash, sourced from up and down the West Coast, hoping to find the rare tree with genetic resistance to the Emerald Ash Borer.
About one in 1,000 trees, or five of the 5,300 seedlings here, may be able to survive the beetle infestation, according to Dorena Center geneticist Richard Snieszko. “We’ve labeled each seedling, so when they're planted out, there will be a tag on it. So we'll know which parent tree it came off of.”
It’s a gamble, but it could put the West Coast a step ahead of many other states, where people are now finding a few so-called “lingering,” living ash trees, and propagating them.
The invasive Emerald Ash Borer, or EAB, was first detected in Michigan in 2002. Its larvae have killed hundreds of millions of trees. By the time the beetles are spotted, they’ve likely been in an area for years. They can’t be exterminated.
Oregon Ash grows from British Columbia to southern California. It’s common in the Willamette Valley, and helps cool waterways and filter pollution.
Ash is also a popular street tree. The City of Eugene reports nine percent of its trees are Ash varieties. Snieszko said urban tree removal has cost eastern states hundreds of millions of dollars. Then there’s the loss of shade and the related human health toll.
“What I like to tell people," he said, "is that when some of these come in, sooner or later we have to realize that most of the standing trees, maybe 90, 95%, 99% of them, are gonna be gone.”
A freezer at the Dorena facility houses a potential backup solution. At 0° Fahrenheit, it's shockingly cold. Snieszko said more than 40,000 seeds from various regional trees, including Oregon ash, are preserved here. Some Oregon Ash seeds have been sent to other seed banks, including one in Fort Collins, Colorado.
Being late to the invasion gives Oregon some advantages. Wyatt Williams, the Invasive Species Specialist with the Oregon Department of Forestry, said that includes working with the beetle’s natural predators, or “biological control agents."
“We’ve had 20 years of science," he told KLCC. "So we have science on forest genetics, we have science on biological control. Thanks to the USDA and ODA, we were able to release biological control agents the first year. No other states are able to do that.”
Williams added the ODF began proactively collecting Oregon Ash seeds in 2019. It’s those seeds that have become the seedlings at the Dorena center.
But Snieszko cautioned there’s a limit to how many trees can be saved.
“The individual trees that you value, there are, I think, chemical treatments that you can do," he said, "but, you know, we can’t treat millions of trees every year or every other year, across a forest landscape, so that's not really a solution.”
Because the Dorena center is internationally known for studying tree’s resistance to pathogens, he proposed breeding ash from various locations and planting the tagged trees.
“When the Emerald Ash Borer comes through, we'll see what's left," said Snieszko. "We'll know what the parent tree is, and then can get back to that tree and can maybe graft it into an orchard or root it or whatever.”
Williams said the seedlings raised in Dorena will be moved to four northern Willamette Valley plots this fall.
“One of the test locations is going to be at the ODF seed orchard outside Saint Paul, which is right in the middle of the two known populations of EAB in Oregon, that being the Forest Grove population and the Woodburn population," he said, adding: "It's not inconceivable to think that EAB could be right there, right now.”
The Emerald Ash Borer has been found in six new locations in 2025. Multnomah County was just added to the list, with a confirmed sighting in Portland. Williams said the website OregonEAB.com has a map with a thick red line around the known sites. That’s the quarantine area.
“If you are inside the quarantine area, please do not move wood as you're camping this fall, especially," said Willams. "Source your firewood at your destination, where you're gonna be camping.”
On the Oregon EAB website, you can type in an address and find the current guidance for that location, and residents can help state scientists by reporting suspected beetle signs online, or calling the state’s invasive species hotline at 1-866-INVADER.
People can also contribute by learning to identify ash trees and the signs of infestation. Snieszko was impressed that more than 1,000 people signed up to gather Oregon Ash seeds this fall for future propagation, and he says people can help after the beetle goes through.
“If there's different people to monitor their areas and say, 'Hey, 99% of trees are dead, but here's a living one that's pretty big and how come it's not dead?' It’s really up to you to help us find those rare parent trees that actually survive,” he said.
