Caused by an apparently non-native water mold, Phytophthora ramorum, the disease has infected and killed large stands of western oaks with alarming suddenness. Since first appearing in California during the mid-1990’s, the disease has been spreading rapidly.

“People tend to not care about plants and forests as much as we do about humans and animals, but sudden oak death could be a bird flu of the plant world waiting to happen,” said Ross Meentemeyer, a landscape ecologist at the University of North Carolina at Charlotte. “This may be even worse than chestnut blight in its impact on our forests, since it is affecting multiple keystone species.”

Meentemeyer and colleagues have determined fire suppression and other land-use practices have altered the structure and composition of forests in a manner that might facilitate the spread of the disease.

”More connected forests have more disease,” said Meentemeyer. “Smaller and more isolated forests have less disease.”

The research is to be presented in a forthcoming issue of the journal Ecological Applications.