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In Longfellow, a divide over how to deal with a common tree killer: emerald ash borer

A decision to treat trees with emamectin benzoate has drawn opposition from residents.

The Longfellow Community Council plan to treat up to 20 privately owned ash trees with emamectin benzoate to combat the emerald ash borer.

The Longfellow Community Council will begin a new plan this week to chemically treat neighborhood trees for emerald ash borer.

On Wednesday, the south Minneapolis neighborhood council will begin collecting participants’ names and planning the lottery system to treat up to 20 privately owned ash trees with emamectin benzoate — a pesticide that’s injected straight into the vascular system of ash trees and known for being highly effective against EAB infestation. Minnetonka-based Rainbow Tree Care will perform the treatments.

Residents who qualify for the grant program will pay half the treatment cost, with the other half paid for with council funds pulled from the neighborhood’s public gardening programming. The total cost of the project — at just above $4,100 — will run about $200 per tree, council officials said, which is far lower than the cost of removal and will allow the ash trees to continue providing benefits like shade and air purification until newly planted trees can mature.

But the decision was met with significant resistance from both residents concerned that the pesticide might endanger pollinators like bees, and by council members who expressed doubt in the efficacy of using public dollars to pay for a temporary solution for trees on private property.

A heated debate

The controversy began on Oct. 3, when about 25 residents attended an LCC community input meeting about chemically treating neighborhood ash trees. “For a community council meeting, that’s a lot of people,” said Anni Murray-Rudegeair of the LCC’s ad-hoc environmental committee.

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Some residents were very vocally opposed to the measure, Murray-Rudegeair said, while others simply didn’t know enough about the treatment and were skeptical of the idea before coming around. “This is a complicated thing, and there are people on both sides,” she said.

Russ Henry, who strongly opposes the treatment plan, said he and several other residents showed up because they believe that using any pesticides on neighborhood trees will potentially endanger pollinators like bees, butterflies and birds.

Julia Vanatta, who’s lived in Longfellow for 39 years, said what she learned from the Dutch elm disease epidemic is that the trees will need to be replaced eventually, and thinks using pesticides during the interim is an unnecessary risk. “They’re going to get infected because emerald ash borer is here,” Vanatta said. “If we delay planting new trees … we’re just delaying the inevitable.”

Some community council board members also expressed doubts over the plan’s efficacy, and whether it was appropriate to use public money to treat private trees, according to documents provided by the council. LCC Board Member Lisa Boyd felt that the $2,000 needed for the program was “a lot of money for treating only 20 trees,” according to the minutes of the Nov. 17 council meeting, and she questioned if it would be worth the additional time and energy to organize.

Board Member Trevor Russell also expressed opposition to the plan on Facebook. “I’d prefer we just replace at-risk trees with new ones,” he wrote in a post.

But several board members expressed support of the treatment, saying it would provide a higher standard of living for those affected by EAB-infected trees while they wait for newly planted trees to mature. In the end, the LCC board voted 6-5 to pass the measure, with two members abstaining.

How much risk? 

Despite public concern over adverse health risks, Jeff Hahn, a leading EAB entomologist at the University of Minnesota, said the vast majority of entomologists agree that when used properly, emamectin benzoate has a very low risk of harming pollinators or humans. “There are potential pros and cons to any of these methods,” Hahn said. “But if you are using them intelligently, you’re following labeled directions, you can certainly greatly minimize any potential risks.”

Because of the way the pesticide is injected into trees and because ash trees pollinate using wind, insects like bees and butterflies are highly unlikely to encounter the poison. “I do not have any issues with ash trees being treated,” he said. “I think what sometimes gets forgotten here is the value of healthy trees.”

But Vanatta, among others, still isn’t convinced of emamectin benzoate’s safety, pointing to the EPA’s recent decision to reverse its stance on neonicotinoids — the most widely used insecticides in the world — admitting the pesticides have been killing bees in record numbers after claiming they were safe for more than 20 years.  “Anytime you’ve got a pesticide that’s been out there for 15 years, you’re just beginning to see the data on health risks,” she said.

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Cheaper ‘in the long run’

Longfellow won’t be the only Twin Cities neighborhood choosing to treat their ash trees as a cheaper alternative to removal. While treating a tree can cost up to $200, removal can easily run into the thousands, and other neighborhoods like Marcy-Holmes and St. Anthony West have already begun treating their ash trees on an annual basis.

Yet Ralph Sievert, the Minneapolis Park and Recreation Board’s director of forestry, said that “in the long run,” it’s actually cheaper to just remove the ash trees and begin replacing them immediately. Treating trees must be done every two years, Sievert said, and eventually those trees will need to be removed, either because they’re already infected or because more overall tree diversity is needed to prevent future outbreaks. That’s why the city bucked treatment in 2013, he said, and began replacing boulevard ash trees over a projected eight-year plan.

Look to Milwaukee, Wisconsin, for example, Sievert said, where they’re spending $2 million annually over two decades to treat their ash trees. Alternatively, he said, Minneapolis is spending about $1.5 million over eight years and will have a healthy diversity of trees in the end.

Minneapolis’ approach also avoided a potentially nasty public fight over using pesticides, Sievert said, which was an added bonus.

“By doing the removal and replacement we’re going to do anyway, we won’t even have to talk about treatment and how it may affect pollinators,” he said.