Field Notes

Emerald ash borer: You can help save Vermont’s ash trees

8 min read / March 14, 2022

A threat to 5% of Vermont's trees

After watching it sweep across much of the country, we weren’t surprised when this destructive insect arrived in Vermont in 2018. The insect has the potential to destroy nearly all of Vermont’s ash trees, about five percent of our forests. We have hope that we can slow the spread and help save these beautiful trees.

Learning about the insect is the first step

On a perfect summer day, 40 foresters gathered on woodland in Rupert, Vermont. They were here to learn more about managing forests with ash trees, given the threat of emerald ash borer. The larvae of this invasive beetle chew tunnels under the bark; this cuts off water and nutrition and usually kills the tree.

Forester Alan Calfee hosted the workshop on land he conserved with the Vermont Land Trust. He helps manage around 25,000 acres on parcels ranging from 20 acres to 5,000. Emerald ash borer hadn’t yet been found in these lands, but people are asking him about it.

“The workshop was a bit of an awakening for me,” he reflects. “It really hit me that this pest is here. We have to start managing the forests for emerald ash borer now.”

Why we shouldn't cut all ash trees now

Vermont is the 31st state with confirmed EAB so it might benefit from what other states have learned.

“Just recently, people assumed emerald ash borer would kill nearly every ash tree,” says VLT forester Pieter van Loon. “But new research suggests there’s more variability.” While some places have seen almost no survival, 75 percent of white ash survived in parts of Michigan, which has had emerald ash borer for 17 years. No one knows why. “The take-away is don’t cut all your ash, because some may live.”

“We have to do whatever we can to create an understory of ash,” Alan adds, “so that if the bug takes out the overstory we have the greatest chance of getting new trees to seed-bearing age.”

Female ash trees are critical to the tree's survival

Alan advises people to be aware that ash trees are either male or female, and while a single female tree needs several male trees nearby, it is also important to maintain large, healthy female trees “so there are seeds for the future.”

This picture shows a stand of ash being blown around by a brisk south wind. There are lots of red and yellowish clumps of seeds on the ash in the center of the photo. Almost all the rest have no seeds. The center tree is female and they are surrounded by males.

“Turns out, the recommended ratio is 6-12 male trees left for every female,” explains Pieter. “This is to be sure there is enough pollen to blow around and fertilize the female flowers. If your next timber sale is more than a year away and you want to retain some ash trees with the goal of getting some regeneration, you might want to go out when there are seeds and mark the males and females.”

“It’s about saving a species”

Alan sees hope in owners of conserved land. “The land trust has a population of forest owners who think long-term and can make a difference.” He adds, “It’s about saving a species.”

Here are some tips for managing your woods for the the future of ash trees

We can reduce damage from emerald ash borer by continuing to learn and applying best practices.

Not all is lost! There are ways that landowners, foresters, loggers, conservation organizations and community leaders can address the loss of ash from our forests and help ash species survive. We joined with other groups to create this publication, Managing Northeastern Forests Threatened by Emerald Ash Borer.
Don’t listen to advice to cut all your ash trees now. Recent research shows white ash can survive at much higher rates than previously thought. If you are wondering how to react to the news of EAB in VT, have a look at these recommendations.
If you live in an area with a known infestation, contact your county forester for advice on 1) what to do about the insect and 2) to make sure any actions you take in your woods will keep you in compliance with the Current Use Program (should you be enrolled). Find you local county forester.
If you are within the infested area, and your forest is being logged, be sure to follow these recommendations for the movement of forest products harvested within the infested area to other locations within the federal quarantine boundary, which includes the rest of Vermont.
Although the emerald ash borer kills all species of ash trees it infests, trees don’t die immediately; rather they will shows signs of infection for some time. Learn how to detect signs of emerald ash borer and, if you think you’ve found some, report it here.
Do not move firewood. This is so important to slowing the spread. Buy or harvest your firewood as close to where you burn it as possible. Moving wood between locations can transport the insect or its larvae, speeding its spread.