With the emerald ash borer (EAB) now found in all 14 Vermont counties, state forestry officials are encouraging homeowners to assess the health of their ash trees and consider steps to protect or remove those at risk.

“Brandon does not yet have a confirmed EAB detection, but it is only a matter of time before that changes,” said Noah Hoffman, invasive species coordinator at the Vermont Department of Forests, Parks, and Recreation.

Native to Asia, the EAB lays its eggs in the crevices of ash tree bark. When the eggs hatch, the larvae burrow beneath the bark and feed on the tissues that transport nutrients through the tree, eventually causing its decline and death.

Adult beetles live for about three weeks. They are most active during the day, particularly when the weather is warm and sunny. They remain active until the end of summer.

How to identify an ash tree

Ash trees have compound leaves, typically made up of five to nine leaflets arranged along a central stem. Their branches and buds grow in opposite pairs, rather than alternating along the branch. Mature ash trees often have gray bark with a distinctive diamond-shaped pattern of ridges.

Female ash trees also produce clusters of paddle-shaped, winged seeds that often remain on the branches into fall and winter, making them another useful identification feature.

If you’re not sure whether you have an ash tree, the Vermont Urban & Community Forestry Program’s illustrated homeowner’s guide can help you identify the trees and recognize signs of infestation.

Spotting an infestation

Signs of an EAB infestation can include dead branches near the top of the tree, excessive branching on the tree trunk, and vertical cracks in the bark.

Other telltale signs are S-shaped tunnels beneath the bark created by feeding larvae and small D-shaped exit holes left by emerging adult beetles.

Increased woodpecker activity can also indicate an infestation. Woodpeckers often strip away the outer layers of the bark to eat the larvae beneath it.

What homeowners can do

Hoffman encourages homeowners to assess their ash trees now, particularly those near homes, roads, driveways, or other areas where falling branches or trees could pose a hazard.

Infested ash trees can decline rapidly and become increasingly brittle, making them more dangerous and expensive to remove.

Healthy ash trees may be candidates for protective insecticide treatments, but treatment is generally less effective once a tree has suffered significant damage. Homeowners should consult a certified arborist about treatment or removal options.

Slowing the spread

Although adult beetles are no longer flying and seeking new host trees during the fall and winter dormant period, EAB larvae can survive beneath the bark of infested wood. Moving firewood or ash logs can spread the pest to new areas.

Vermont has restrictions on transporting ash wood, but the rules are less restrictive during the dormant season. Under a recent joint executive order, ash wood may be transported through towns without confirmed EAB detections, provided it travels directly to a destination in an infested town without stopping along the way in any towns without confirmed EAB detections. During the beetle’s flight season, transportation is limited to within a single infested town or between adjacent infested towns.

Residents and campers are encouraged to buy firewood locally and burn it where they buy it. Vermont state parks, state forests, and the Green Mountain National Forest permit only Vermont-origin or certified heat-treated firewood.

Residents who suspect EAB in areas without confirmed detections should report their findings. Hoffman says early detection is important to help communities protect their remaining ash trees.

For more information, visit Vermont Invasives or the Vermont Department of Forests, Parks, and Recreation.