Ny Foresters Wary Of Oak Wilt Latest Tree Threat

02.09.14 | Bob Price

Terry Phillips will be sorry to see the last two massive oaks in his yard reduced to wood chips this spring, but he knows it has to be done to keep a devastating fungus from getting a root-hold in New York.

Phillips' home in the woodsy subdivision of Glen Oaks is at the epicenter of the state's first and only known outbreak of oak wilt, a swiftly lethal fungus that has destroyed hundreds of thousands of trees in states where it has become established. The nearest known outbreak was 200 miles away in Erie, Pa., when the fungus first showed up in Glenville, 15 miles northwest of Albany.

"Trees started dying in 2007," said Phillips, a retired nuclear engineer, sitting at his dining room table with a picture-window view of a 100-year-old oak equipped with a tire swing. "I had an arborist friend look at the trees, and he said it looks like oak wilt. But when I called the Cooperative Extension, they said it doesn't exist in New York."

Phillips took a branch from a neighbor's sick tree to be tested; the disease was confirmed. The Department of Environmental Conservation and the U.S. Forest Service mapped out a plan that called for removing every oak within a 150-foot radius of a diseased tree. In spring 2009, about 100 trees were reduced to chips and their stumps treated with herbicide.

Phillips was allowed to keep two huge oaks after he agreed to spend $2,500 to have a trench dug around his yard to prevent the roots from contacting infected roots, the chief mode of disease transmission. The Forest Service declared the eradication effort "a forest health protection success story."

But last summer, Phillips noticed wilting leaves on one of his remaining trees. The disease was back. State foresters believe the tree was infected when roots grew into an area still contaminated by fungus from sick trees that had been removed.

"We're fairly confident this is an isolated outbreak," said Jerry Carlson, chief of forest health for the state Department of Environmental Conservation. "We need to get the trees removed and the remaining high-risk area treated by the end of March."

Oak wilt is a significant killer of red oaks in the upper Midwest and Mid-Atlantic states as well as in Texas, according to the U.S. Forest Service. It can kill trees within three months.

"We're constantly looking for this particular disease," Carlson said. "We have an annual detection strategy where we send trained forest health crews out to inspect symptomatic trees."

Foresters suspect the disease arrived in Glen Oaks in firewood a homeowner brought from Wisconsin. The fungus is carried by bark beetles and transmitted from tree to tree through roots.

Oak wilt is the latest in a number of new threats to Northeastern forests. The emerald ash borer first appeared in the U.S. in 2002 in southeastern Michigan and was found in western New York in 2009. It has since spread to much of the state and into New England.

"Asian longhorn beetle is active in Massachusetts, New York City and Long Island, and we're trying to make sure it doesn't move up into sugar maple stands up north," Carlson said.

"We're also concerned about two-lined chestnut borers, which are becoming increasingly problematic in red oak stands," Carlson said. "Another one we're concerned about is the southern pine beetle, which was recently shown to be moving into large pine stands in New Jersey. I'm concerned about the Albany Pine Bush and other pine stands; it may become more of a problem with climate change."

New York has a prohibition on moving firewood more than 50 miles unless it's been heat-treated to kill pests.

"We do helicopter surveys annually in the Glenville area looking for symptoms of oak wilt, and we also look for it statewide in our aircraft surveys," Carlson said. "We're trying to be on top of it."