In 2001, forest pathologists in Oregon discovered what was killing trees in Curry County in southwest Oregon – a devastating disease known as sudden oak death. Almost 20 years later, sudden oak death hasn’t spread beyond the county’s borders.
Although the initial goal was eradication, limiting sudden oak death’s spread proved to be a success, said Everett Hansen, a now-retired Oregon State University professor who helped spearhead the effort to contain the spread of the disease.
“From day one, we invoked legal machinery to mandate the destruction of diseased trees,” Hansen said. “Every time we found a diseased tree we cut it down as fast as we could. We were going full bore. So, we went through all these years without any published data to suggest what we were doing was working.”
In a new study published in the journal Forest Pathology, Hansen and colleagues at the Oregon Department of Forestry and U.S. Forest Service highlight the successes of the two-decade effort to manage and reduce the spread of sudden oak death in Oregon.
In 2001, federal, state and local agencies marshaled their resources to manage the outbreak. They quarantined areas where the trees had been infected and cut down and burned sick trees.
“We focused on local treatments instead of landscapes, sometimes by design but sometimes out of necessity,” said Hansen, lead author on the study. “If it was one tree and we cut it down and all the surrounding trees for a mile we might well have eradicated it. But we never had that chance. We didn’t have enough chainsaws.”
However, the researchers found that these treatments did demonstrably reduce the infestation. They concluded that eradication of sudden oak death is difficult — the pathogen that causes the disease may survive in soil for several years – but not impossible.