DOT’S BEAT: To Save our Ash Trees, Cut or Treat?

by Dot Helling

Shortly after I wrote a piece this spring warning about the threat of the emerald ash borer, borers were found in Montpelier near National Life. Since then our tree board and tree warden have been tirelessly working on an emerald ash borer management plan. With the help of many volunteers, their recent survey identified 450-plus ash trees along streets in our beautiful city of trees, in addition to 200-plus along park pathways, plus a previously estimated 2,700 on private property. What are the steps being taken to address this crisis? Why act and not just let nature take its course?

According to John Snell, tree board chair and ash borer first detector, if nothing is done to combat the ash borer, all of our ash trees will die in the next ten years. There are a number of ways to address the future of an ash tree, depending on whether or not it is infested and to what extent. Early discovery of borers is critical to extending the life of these trees that provide our downtown with shade, stormwater control, and canopied beauty.

But, once discovered, what’s the best method of treating?

Vermont municipalities are taking different tacks. Rutland is taking a proactive approach and removing all of its ash trees citywide before detecting the presence of borers at an estimated cost of $90,000. This decision is a financial one, having determined that the removal of live ash trees before any infestation is more economical than waiting, treating, and removing dying ash. Williston plans to remove 42 percent of its ash trees and replace them with maples, elms, and other diverse species. Burlington estimates it has 1,275 ash trees within the city. City officials anticipate a long-term cost of $400,000 to $720,000, with plans to treat 50 to 75 percent of their ash trees and remove the rest.

Whatever approach a municipality takes, timing is critical. Infested trees should not be moved during flight season—May through November—and must be treated in the spring prior to the adult borers laying eggs on the trees.

The Montpelier Tree Board proposes to slow down the infestation by treating 15 downtown ash trees and others in Hubbard Park with a chemical called emamectin benzoate, aka TREE-äge. The tree board advises residents to use professionals if they want to treat their personal trees and under no circumstances use any neonicotinoids (“neonics”) such as imidacloprid or dinotefuran, which will kill pollinators and pose carcinogenic dangers to humans and wildlife.

Although treatments in Canada and other parts of America have failed to save the ash trees, treating with TREE-äge can extend the lifetime of the trees without posing a threat to the public. It is injected into the tree under controlled conditions to ensure no direct exposure to humans or wildlife.

Ash trees are protected from the borers only as long as they are treated. Montpelier’s plan is to treat in order for downtown ash to survive as long as it takes for replacement trees to sufficiently establish themselves and hopefully avoid what tree board members visualize as a “moonscape” or “wasteland” in the downtown if all the big green ash trees were to go at once. There is also a possibility that unknown advances in treatment may become known within the near future.

The treatment plan proposed for Montpelier’s 15 trees would cost an estimated $1,000 per year for TREE-äge, which would be re-injected every two years beginning in the spring 2019. Fifteen trees total a cost of about $15,000 over the course of 10 years for the chemical. In addition to treatment and application costs, there is the eventual cost of removal when the trees die. There is discussion about using “trap trees,” which might draw the emerald ash borers to trees that are treated in order to destroy them.

There are no easy answers. Either way is a trade-off. Choose not to treat, and we lose our grand ash trees sooner. The bottom line is all about the money. Do we spend what some perceive as unrecoverable dollars on forestalling the inevitable, or do we grab at the “hope” of extending the life of our trees and holding onto some of our precious treed canopy up to a decade longer, perhaps even saving an ash tree or two?

Some see this as a debate between treehugger and taxpayer, in a city where high taxes are making life unaffordable. Add your voice and come to a city council meeting that has the emerald ash borer as an agenda item, talk to the tree board and warden, and certainly take a proactive role in identifying the presence of borers and managing infested trees on your properties.

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