TANGENT, Ore. — The Calapooia River flows past fields of bucolic farmland in the Mid-Willamette Valley where Don Wirth walked over to inspect a fallen ash tree along the stream bank.

Wirth, whose family has lived and farmed near Tangent, Ore. for 73 years, recently began noticing dead and dying ash with alarming regularity. He points out trees with skeletal bare tops that stick out like a sore thumb in densely wooded stands.

“I’ve been looking at them long enough they just stick out at me,” said Wirth, touring around the area with his energetic dog, Pep. “You just gotta be observant.”

Wirth estimates there are about 200 acres of native Oregon ash trees on his family’s farm. With the recent arrival of the invasive and highly destructive emerald ash borer, he worries they will all be gone in the next 10 years.

In May, Wirth hosted David Shaw, a forest health specialist with Oregon State University Extension Service, to take a closer look at what’s afflicting ash locally.

They didn’t find any signs of emerald ash borer, but some trees did bear the telltale marks of another pest, the ash bark beetle, while others likely succumbed to a fungal disease known as heart rot that causes the center of the trunk and branches to decay.

Experts predict it is only a matter of time before emerald ash borer spreads, bringing widespread tree mortality. That is raising questions for landowners like Wirth about next steps, including how to dispose of the dead wood and which species are suitable to replant.

“I’d like to see some leadership,” Wirth said. “Tell us what we can do.”

EAB task force

Emerald ash borer, or EAB, was first discovered in Oregon in June 2022 in ash trees at an elementary school parking lot in the Portland suburb of Forest Grove. It was the first known sighting of the metallic green, tree-killing beetle on the West Coast.

In response, the state Department of Agriculture convened a task force composed of regulatory agencies, industry leaders, city officials and natural resources managers to plot their response and field questions from the public.

“We have a whole lot of interest in this insect,” said Cody Holthouse, program manager for insect pest prevention and management at ODA.

The task force is broken down into seven subcommittees focused on surveying and monitoring; best management practices; wood utilization; research; communications; landowner training; and a steering committee.

Shaw, with OSU Extension Service, said there have been few studies done in the past about Oregon ash. But with the emergence of EAB has come a surge of interest.

Earlier this year, Shaw co-authored a paper with George Kral at OSU outlining possible replacements for ash trees across Western Oregon.

Their recommendations are based on a site’s soil moisture, characteristics and ecological functions.

Based on the effects of EAB in the Midwest, where it has killed hundreds of millions of trees, Shaw said he is “a little depressed” about the fate of Oregon ash.

“We’re likely looking at 99% mortality of the Oregon ash,” he said. “That’s consistent with what they’ve been seeing back east.”

Buying time

Slowing the spread of EAB has been at the forefront of efforts led by ODA and the Oregon Department of Forestry.

A quarantine remains in effect for Washington County, Ore., restricting the movement of olive, ash and fringe white tree material — including firewood — that could harbor the beetle.

So far, Holthouse said there have been no reports of EAB outside Forest Grove. A team of seasonal technicians has visually inspected 9,152 trees within a 50-mile radius of the city, finding 53 that were infected, all within 1.5 miles of where it was initially detected.

In order to fortify their defenses, Holthouse said workers have set up network of “trap” trees that have been girdled, stripping away bark around the circumference of their trunk.

This stresses the tree, causing it to emit airborne compounds that attract EAB. Once they are drawn into the trap, they can then be killed.

Holthouse said ODA has also been working with the USDA’s Animal and Plant Health Inspection Service to release three species of tiny parasitoid wasp about the size of a typical mosquito that lay their eggs inside EAB eggs and larva, killing them before they can grow and develop.

The wasps do not sting and are harmless to people, Holthouse said. More than 5,000 of the wasps were released in June after arriving from an APHIS lab in Brighton, Mich.

Meanwhile, ODF has set traps for EAB in the canopy of ash trees from Sauvie Island on the Columbia River near Portland south to Eugene, covering nearly 130 miles.

Though they are putting up a fight, Holthouse said it is likely EAB will eventually spread. What they are really doing is buying time, he said, for communities to prepare.

“These wasps will help bring somewhat of a normalcy to the (EAB) population, but they won’t fully eradicate it,” he said.

More questions

Oregon ash trees are in “extreme danger” of going extinct due to EAB, Holthouse said. Perhaps the only hope, he said, is finding some kind of genetic resistance in an individual tree that can be bred into future generations of ash.

“That’s a long shot, though,” Holthouse said. “Resistance is a complicated thing.”

If that happens, Shaw said it will take more work to rehabilitate riparian areas in lower elevations where the trees thrive, ensuring they can continue to provide ecological benefits including bird and wildlife habitat and shade for streams.

“There are a lot of issues I think we’re still working out,” Shaw said. “The most difficult thing is what do we do with all the wood?”

Wirth, whose father was a logger before the family pivoted to growing hazelnuts and seed crops, said it is still not clear what they are going to be able to do on their land. He is hoping to get better direction from state and federal agencies soon.

“I don’t like to complain and not be a part of the solution,” he said. “Let’s get this resolved now.”

To report possible sightings of emerald ash borer, call the Oregon Invasive Species Hotline at 1-866-INVADER, or visit www.oregoninvasiveshotline.org.

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