Emerald Ash Borer infestation canopy dieback

Emerald Ash Borer Awareness Week is May 23-29, 2021 and it’s a great time for citizens to familiarize themselves with the signs of infestation and learn how to protect ash trees.

“This invasive pest has been in Tennessee for more than a decade and, unfortunately, it’s here to stay,” State Forester David Arnold said. “Awareness of the beetle, the symptoms, and the destruction it causes can help homeowners and woodland owners make informed decisions. We want residents to understand the time will come when they have to decide what to do with their dying ash.”

The borer kills a tree by creating tunnels as they eat through the tree’s nutrient conducting tissues. They destroy the channels that transport water from the tree’s roots to its leaves, as well as the sugars produced in photosynthesis flowing from the leaves to the roots. Once attacked, small trees may die within 1-2 years of becoming infested and large trees can be killed in 3-4 years. If caught early enough, infested ash trees can be treated and protected.

Homeowners should monitor their ash trees for signs and symptoms of EAB. One of the first signs is canopy dieback of the upper branches. If left untreated, the tree will die. If the ash tree still looks healthy, the time to protect the tree is now. Once it’s in decline, it may be too late. Either way, there is a cost to treating a live tree or removing a dead one. For large dying or dead trees, homeowners are advised to hire an ISA Certified Arborist to remove the tree. If a certified arborist is not available in your area, ensure that the tree care company has liability insurance and worker’s compensation insurance to protect you from damage and/or injury costs. Certified arborists can also be hired to treat healthy trees effectively keeping them alive for years despite local infestations. Smaller healthy trees can be treated by the homeowner with over-the-counter insecticides labelled specifically for the borer.

Woodland owners with forests consisting of ash are advised to work with a consulting forester to determine value of their ash and develop a plan for extraction, if feasible with the owner’s objectives. Left standing, the ash component of the forest will face decline as there currently is no effective large-scale treatment other than treating individual trees.

The Tennessee Department of Agriculture Division of Forestry estimates there are 240 million ash trees in Tennessee. This represents a decline of more than 20 million ash trees in the last decade, which can likely be attributed to the spread of EAB. Ash remains a valuable hardwood species to the forest products industry and prices for ash logs remain strong despite the toll EAB has taken on log availability. There are 91 mills in Tennessee that process ash logs. Ash is also a valuable urban forest tree for its shade and tolerance to compacted soils. The species are also important to wildlife for food and shelter.

For more information about EAB and other destructive forest pests in Tennessee, visit www.protecttnforests.org. Follow @ProtectTNForests on Facebook, Instagram, and Twitter for updates on the harmful effects of insects and diseases, where pests are found, and what landowners can do to protect their trees.