Emerald ash borer eats its way through Door County trees

The invasive emerald ash borer is killing thousands of trees in Door County.

Wisconsin Department of Natural Resources officials told Wisconsin Public Radio that the highly destructive beetles have killed tens of millions of trees across the country since first being spotted in North America in 2002.

The beetle was discovered in Door County in 2014.

According to the U.S. Forest Service, the Door County peninsula has 12 million ash trees, which is roughly 13 percent of the county’s tree inventory. Many of the ash trees are on city, county or state property and more are on private land.

Natural Resources Department forester Bill Ruff said individual state and county parks in Door County have their own plans to deal with the pest and that the agency doesn’t plan to treat ash trees on its land.

“The main concern for those are safety concerns in public use areas,” he said. “If they become ‘hazard trees,’ then that’s something they have to pay attention to and make sure there isn’t a public safety risk as a result.”

He said the borer has no natural predator and that the situation is “bleak.”

“We’ve reached the point now where we have almost half the townships in the county (with) confirmed locations with the ash borer, so the spread is on,” Ruff said.

The beetle was first found in southeastern Wisconsin in 2008, according to the state’s Natural Resources Department.