Sudden Oak Death

A forest disease is slowly creeping towards Coos County.

Forest officials last month discovered new cases of the sudden oak death pathogen south of the county line in Curry County.

The disease isn’t new for the county — around a third of it is within a quarantine area, where some plant transport is prohibited and eradication is required. But forest experts are raising concerns about how far away the new cases are from previously known ones.

“That distance indicates to me that we have much larger spread,” said Sarah Navarro, a forest pathologist with the U.S. Forest Service. “It is concerning that it’s a new location so far away from any of the other sites farther south.”

More specifically, researchers located one infected tree just outside the current quarantine area, and another case 21 miles north, near Port Orford.

The disease — known by its technical name Phytophthora ramorum — infects tanoak trees with spores that pass through the forest canopy during spring and fall winds. Once infected, a tree’s canopy dies back and develops oozing cankers, which completely kill the tree in a year or two.

“In terms of tree years, it’s sudden,” Navarro said.

It can infect over 100 native and nonnative plant species, according to Navarro, though the impact is most pronounced with tanoaks, which drive the disease’s spread in Oregon’s forests.

The deaths have concerned Oregon forest officials for 20 years since it was first introduced. Unabated, the disease could damage forest industry profits, cultural resources and could even result in international sanctions on timber exports from the port of Coos Bay, according to a 2019 study.

Still, a group of state and federal land management agencies have plans in place for responding to the disease.

“The program originally started as an eradication program in 2001,” Navarro said. “But that eradication is no longer a possibility.”

Now that sudden oak death is well established in Curry County, Oregon’s forestry and agriculture departments and federal foresters are focused on slowing the spread of the disease, instead of getting rid of the disease altogether.

To do that, there’s a system in place for responding to new cases of the disease.

So when an Oregon State University forestry researcher spotted dying tanoaks on the highway near Port Orford late last month, they launched into action.

Since the cases were outside the established quarantine zone, the detection triggered an emergency three-mile quarantine zone around the tree. Samples were sent to an OSU lab to confirm the strain of the disease. If confirmed, the trees await a somber fate.

That’s what happened at the other recently located sudden oak death site north of the quarantine zone: The infected trees, as well as all the tanoaks around them, were chopped down and piled up, ready to be burned when wetter weather returns.

“For sudden oak death, the only tool that has proven to be effective has been removing the host,” Navarro said. “By removing the tanoak in a specific buffer around that diseased tanoak, we’re also hopefully treating diseased tanoak that we can’t see.”

At the Port Orford site, officials are still waiting for lab confirmation of the disease, aerial surveys and the consent of nearby landowners to figure out the extent of the spread.

Once that’s determined, the state and federal agencies will initiate quarantine and treatment regulations to low further spread.

In the meantime, Navarro said landowners in the area can be on the lookout for possible signs of the disease on their property, signaled by the redish dieback of tanoak trees.

“If people are seeing any sort of dieback like that ... definitely contact the Oregon Department of Forestry,” Navarro said. “The more eyes we have out there the better.”


The World's Latest E-Edition

Connect With Us


Load comments