The map showing the extent of the emerald ash borer infestation in Vermont — so far — looks like something an epidemiologist would prepare to show the spread of a dangerous disease. Reachable via a link from the Vermont Invasives website, the map features two ominous-looking red circles, overlapping along Route 14 in Barre and East Montpelier. Highlighted are 11 towns, in Orange, Washington and Caledonia counties, that are within five miles of “confirmed infested areas.” There is a swath of orange depicting “high risk areas” where the infestation is “likely expanding into.” Or it already has happened, and all that remains is to locate the evidence of disease.
Emerald ash borer, first detected in February, in the town of Orange, then in Plainfield and Groton, has now been found in Barre and Montpelier. The beetle, referred to by its initials EAB in the pest world, eats through the inner bark of the ash tree, depriving the tree of water and nutrients, effectively strangling it. Trees infested by the borer are usually dead within three to five years.
Once the presence of the beetle was confirmed by the federal Animal and Plant Health Inspection Service, the branch of the USDA that manages national pest outbreaks, it was inevitable that a quarantine would be put in place. The question was whether it would be on a county-by-county basis, or statewide.
Vermont recently opted for a statewide quarantine, meaning ash wood cannot be moved out of the state to Maine, Rhode Island or five counties in New Hampshire where EAB has not been detected yet. Steven Sinclair, director of forests for the Vermont Department of Forests, Parks and Recreation, said the decision meant the state could focus on trying to limit the spread of the infestation within the state. Had a county-by-county quarantine been put in place, the state would have had the responsibility of enforcing it, he said. The state quarantine will be enforced by the federal government.
“We’re focusing our limited resources on slowing the spread outside of those four towns where we know there’s infestation,” Sinclair said, adding that the presence of the borer in the states surrounding Vermont means it likely will be found beyond the central Vermont region.
Towns and cities in Vermont, many of which already had EAB action plans in place, have responded to the news of the spread of the EAB in various ways, with some advocating fast action and others calling for a more go-slow approach.
Following the discovery of EAB infestation near the National Life complex, the city of Montpelier launched an assessment of its ash trees, focusing on those that could fall on sidewalks or roads in the most traveled parts of the city. City tree warden Geoff Beyer said the city has trained volunteers to conduct initial health assessments of ash trees in the “higher risk areas.” If a tree were to show signs of infestation, branch samples would be taken for confirmation.
For now, the city’s plan is to remove infected trees but leave healthy ones. “If you wait too long,” Beyer said, “it becomes more dangerous and more expensive to remove a tree.”
Felling healthy ash trees would be like aiding the “enemy” in its quest to wipe out ash, he said.
“While the ash borer kills 99 percent of the trees,” Beyer said, there is always a chance that some of the city’s trees would have a natural resistance. It would be a shame to act too fast, and remove a tree that might prove resistant.
Sinclair described Montpelier’s approach as “aggressive” but added that “when you first start seeing evidence of EAB, it’s too late.”
But its approach is not nearly as aggressive as the town of Williston, more than 30 miles from the closest known emerald ash infestation, which already has started removing its ash trees. More than 40 percent of street trees in Williston are one of the three ash species in Vermont, so the town’s conservation commission was concerned about the safety and financial impact from the inevitable arrival of EAB, said the commission’s Melinda Scott.
“We’re looking at a pretty devastating impact in a short period of time,” said Scott, who commented that some streets in Williston are planted exclusively with ash. “Rather than having to come up with a huge amount of money all at once to replace dead ash trees, the town’s approach has been to replace them over time so the budget won’t be impacted.”
The town has gotten grants through the state’s community and urban forestry program for the past couple years to remove ash trees and plant a greater variety of species, including maple and elm. The idea of diversifying is to reduce the devastation should another pest prove fatal to any of its tree species, she said.
In its outreach to the forest industries and to forest landowners, the state has advocated a more go-slow approach. About 5 percent of the trees in Vermont forests are ash, and their lumber is valuable, Sinclair said.
“For forest landowners, we’re telling them not to be rash,” said Sinclair. “Don’t get ahead of yourself and remove healthy ash trees that could have commercial value.”
“If somebody is in Lamoille or Franklin county, there’s no reason for them to panic and cut trees down (in forests),” he added.
Williston and other towns also have an option that owners of large tracts of forestland do not, which is the limited use of insecticide. Bruce Hoar, head of Williston’s public works department said insecticides would only be used to treat large ash trees in the town green.
Barbara Schulz, forest health program manager for the state, said insecticides can be an effective way to preserve a limited number of so-called high value ash trees, such as those along sidewalks or in backyards, but the strategy is not workable in the forests. The insecticide would have to be injected into the trees multiple times a year into the trees by a trained pesticide applicator, she said.
“The trees have to be pretty healthy to begin with — if they’re too far gone, that won’t help,” added Schulz.
Biological controls such as a parasitic wasp that preys on the beetles could have the potential to curb a statewide infestation, she said. EAB research is ongoing and time will tell, she said.
“If we give it another 10 years, we’ll know a lot more,” she said.
The state is encouraging members of the public to report suspected beetle infestations on Vermont Invasives.
