As if COVID-19 weren’t enough, central Virginia is fighting another plague, only this one—the emerald ash borer—threatens our trees. The beetle may look like a tiny jewel— it’s a bright metallic green, small enough to sit on a penny— but it’s been scything down local ash trees like a malevolent Paul Bunyan.
“No ash tree is safe,” says Jake Van Yahres, co-owner of Van Yahres Tree Company, which his great-grandfather founded in 1919 during another pandemic. “If you have an ash tree and don’t get it treated, it will die.”
The emerald ash borer, native to northeastern Asia, was first detected in the U.S. in Michigan in 2002, and in Albemarle County in 2017. The beetle lays its eggs in the ash’s bark in spring; when the larvae hatch, they tunnel through the bark and feed on the layer beneath all summer, effectively cutting off the tree’s nutrients. The following spring, they emerge as adults to eat leaves, mate, and lay more eggs—killing the tree in three to five years.
Katlin DeWitt, forest health specialist with the Virginia Department of Forestry, says ash is a popular landscaping and urban species because it is hardy, fast-growing, and shapely. “After we lost elms, people planted with ash,” she says. Just ask UVA—it has hundreds of ash trees on the Lawn, Carr’s Hill, the East Range, and along Rugby and McCormick roads.
A tree can be protected by injecting insecticide around its base, but the treatment has to be administered by a certified arborist and repeated every two years. If started in time, treatment ($350-$600 per tree, depending on size) can be more cost-effective than removal. But if the tree is significantly damaged, removing it may be preferable; while living ash trees are strong and hardy, dead ones quickly become brittle and pose a danger if they are near a building, roadway, or public space.
Michael Ronayne, urban forester with the city, says Charlottesville is currently treating 37 trees that are particularly large or well-placed; in 2018, the city spent $8,600 on emerald ash borer protection. Ash trees make up roughly 2 percent of the forest mix in central Virginia, but their noble shape makes them common ornamental trees, and their loss will be felt by even casual observers. One of the city’s largest ash trees stands just behind the Albemarle Charlottesville Historical Society building downtown. “Losing that tree would change the entire block,” says Ronayne.
DeWitt recommends homeowners check their ash trees for signs of infestation: patches of light-colored inner bark exposed by woodpeckers seeking the tasty larvae; canopy die-back; sprouting from the tree’s base; and small, D-shaped holes in the bark where borers have eaten their way out. If you see these signs—or aren’t sure whether it’s an ash tree—hire an arborist to evaluate the damage and outline options.
Infected ash trees can be salvaged as firewood, which should be burned that season before ash borer pupae emerge again in the spring—but to prevent spreading the infestation, don’t sell the wood. Homeowners buying firewood should purchase wood from their immediate area, or make sure it’s labeled heat-treated.
Spending money to protect a tree may not seem to make financial sense, but it’s worth it, say many homeowners. “My parents’ house in Charlottesville has a huge ash tree, hanging over the entire house,” says Van Yahres. “It’s being treated, and it’s still up. If we had to take that tree down, it wouldn’t feel like home.”
Correction: The print version of this story reported that the city spent $86,000 on ash borer treatment; in fact, it spent $8,600.