News from the Tree Warden: Emerald ash borer coming to town

Michigan ash tree showing decline due to emerald ash borer. Photo credit USDA.

At some point in the not-distant future an exotic insect, the emerald ash borer (EAB), will make its appearance in Charlotte and kill almost every ash tree in town. The sudden demise of our ash trees is something we need to expect and plan for. The good news is that EAB has not yet been detected in Vermont, although it is present in all surrounding states and Quebec. This means that we have time to strategize and prepare.

There are four levels of action: detection, threat mitigation, planning and management.

Detection: Telltale signs are the distinctive D-shaped exit holes seen on the bark of infested trees and the serpentine galleries, or tracks, carved by EAB larva just underneath the bark. Other signs include branch die-back from the top of the crown and thin shoots, or branches, growing at the bottom of the tree trunk or around lower main branches. For more information about EAB, please go to the link in the tree warden section of the town website. Please contact me if you think you have detected EAB.

Threat mitigation: The first and most important measure to postpone arrival of EAB is to prevent the importation and movement of EAB-infested firewood. This has been the primary vector for the pest. Second, we can remove weak or damaged ash trees, especially along our roadways. EAB will selectively infest weak or dying ash trees first, so if these trees are removed, it will deny the insect a preferred host. Thinning dense stands of trees also ensures that the remaining trees have the growing space needed to remain robust, heathy and able to resist disease and pests of any type.

Planning: State and federal authorities are encouraging Vermont towns to develop EAB preparedness plans. To that end, the Charlotte Selectboard has authorized an inventory of ash trees on town property and in the town rights of way, with a focus on potential future hazard trees. The Vermont Urban and Community Forestry Program has completed, on our behalf, an inventory of trees on town property, and the results can be seen in the town website. A sample inventory of trees in the town rights of way is pending. An EAB preparedness plan will follow.

Management: Some of our ash trees can be saved, but this will require inoculating individual trees with a pesticide every two years. These treatments are expensive, so treatment is only feasible for a small number of trees. For the most part, management will consist of removing dead hazard trees in public areas and along our roads. Removal of dead, diseased, dying or malformed ash trees right now has the double benefit of spreading the cost of ash tree removal over a longer period of time as well as removing likely hosts for early EAB infestation. I have requested the road commissioner to remove weak ash trees along our roads and in public areas. In addition, I will be taking a liberal attitude toward requests for ash tree removal at camps on Thompson’s Point and other town property and within the rights of way. At this stage, however, we are not recommending the removal of healthy ash trees.

If we are lucky, we will be able to enjoy our ash trees for several more years. In the most optimistic scenario biological controls currently being deployed experimentally will keep EAB populations under control. Even in the worst case we will preserve some select ash trees by inoculating them every two years. In any event, when this unwelcome intruder arrives we intend to be prepared.

Upcoming tree events
A Tree Care Workshop will be held from 6:00 p.m. – 7:00 p.m. at the Senior Center on Feb. 15. VJ Comai, Charlotte resident and professional arborist, will offering a short workshop on the basics of tree care, from planting to maintenance of mature trees.

A Tree Pruning Workshop will be held from 10:00 a.m. – 11:30 a.m. at the Senior Center on March 11. VJ Comai, Charlotte resident and professional arborist, will offering a short workshop on tree pruning with field demonstration, weather permitting.