The Oregon Department of Forestry and USDA Natural Resources Conservation Service are partnering to help private landowners in southwest Oregon slow the spread of an invasive tree-killing disease known as “sudden oak death.”
Since the mid-1990s, the disease has devastated millions of susceptible trees in California, including tanoak, coast live oak, Shreve’s oak and California black oak. The disease was first discovered in Curry County, Ore., in 2001. The Oregon Department of Agriculture immediately quarantined a 9-square-mile area, which has since grown to 525 square miles, roughly one-third of the county.
NRCS Oregon has requested up to $500,000 through the Environmental Quality Incentives Program to reimburse landowners for removing infected trees. Priority will be given to landowners within the quarantine area, which stretches from Brookings north to Gold Beach, though anyone who has the disease on their property is eligible to apply for assistance.
Known by the initials SOD, the disease is caused by the fungus-like pathogen Phytophthora ramorum. The disease thrives in wet forest environments, and spreads via airborne and waterborne spores. Symptoms include bleeding cankers on the tree’s trunk and dieback of foliage, eventually killing the tree.
Randy Wiese, the lead forester working on SOD for the Oregon Department of Forestry, said there is no cure for the disease. Infected tanoaks are cut down, piled and burned, along with all tanoaks in a 300-foot radius.
While SOD can infect adjacent Douglas-fir trees, Wiese said the disease is generally non-lethal in conifers.
“Most species, it will get into them and it’s just sort of there,” he said.
Wiese, who joined ODF in 2010, said the problem in Curry County is getting worse every year. They are now battling two strains of sudden oak death, including the North American strain and an even more aggressive European strain. The top two areas for treatment he said, are along the Winchuck and Pistol rivers.
“The European strain is our focus,” Wiese said. “If we can, we’ll do a larger treatment because of the aggressiveness and the concern.”
SOD is a hazard for landowners because dead trees pose an increased fire and safety risk, Wiese said. From an economic perspective, the quarantine has burdened Curry County with restrictions severely limiting firewood sales and other forest products.
The state quarantine prohibits harvesting tanoak from known infested areas, though producers can request a “pest-free production site” permit within the quarantine from ODA and ODF.
Curry County is the only location of sudden oak death in Oregon forests, though ODA has also found the disease in a small number of nurseries since 2003. More than 135 plants have been proven to be hosts, with the five most common including camellia, pieris, rhododendron, viburnum and kalmia. If SOD is found, a nursery must follow a strict USDA protocol that includes a quarantine, destruction of infected plants, tracing the source of host plants and three years of inspection and sampling to assure SOD is no longer present.
For more information, or to apply for NRCS funding to remove trees stricken with sudden oak death, contact district conservationist Eric Moeggenberg at 541-824-8091.