MANKATO – As the killer ash borer nears Mankato, city officials and the Minnesota Department of Natural Resources are working together to remove 50 trees along sidewalks leading to local schools.
Preventive removal is carried out in the hope that the trees will die in the years to come. Removing trees before they succumb to the emerald ash borer, which makes ash trees brittle and susceptible to dropping large branches, is a safety measure, said Justin Lundborg, natural resources specialist for the city.
Replacing ash trees with other species now means setting up new shade trees for the courses.
“The project is to increase the safety of our busiest public sidewalks,” said Lundborg.
The $ 48,000 project will increase the city’s planned ash disposal by 25% in 2022, for a total of 250 trees. A grant from MNR will cover $ 32,500 of the cost, with the city providing the remainder.
The 50 trees to be felled, which must be within three blocks of a school, are currently being identified and removal is scheduled for this winter and spring. Quality ash trees will be spared and will be considered for chemical treatments that can ward off invasive species.
“It’s just trees that are already in decline, that have bad structure, bad health, things like that,” he said of the removals.
Mankato planned to remove 200 trees this year, a goal that will continue for years to come in hopes of avoiding mass mortality once the emerald ash borer comes in in full force – something that could be beyond the capacity of EMS departments. trees to watch while also hammering the city budget.
The municipal authorities hope to save the best ash trees on the boulevards of the streets and in the municipal parks with the chemical treatments from next summer. But because of the cost of the insecticide, which may be needed as long as the trees live, the plan is to limit treatments to around 350 trees.
Mankato has approximately 2,500 ash trees on boulevards, in parks and on other landscaped municipal lands. So even at 200 tree cuts per year, there is a decade of work to be done.
Lundborg said the city will monitor other grants offered by state and federal governments in hopes of working at a faster pace.
“Anything we can do to increase the numbers and reduce the costs that interest us,” he said.
Lundborg is not resigned to the possibility of the emerald ash borer being discovered at Mankato this year, although it has now been identified as close as St. Clair and has been found in virtually every direction from Mankato.
“We’re crossing our fingers,” he said.
But the city will operate on the assumption that the beetles have arrived, ceasing the ash tree logging in May. The beetles are active during the summer months, so moving the ash wood to a disposal site could then inadvertently give the beetles – which cannot travel great distances on their own – a free elevator into the neighborhoods. not infected.
The goal is to remove the allotment of doomed trees by May, with the fall set aside for chopping stumps and replacement trees planted the following spring, Lundborg said. The insects go dormant again in October, so other tree removal could resume if work is not completed by May.
The emerald ash borer, native to Asia, is believed to have entered North America on imported wood products in the 1990s and has since spread to around 30 states.
It was first detected in 2009 in Minnesota, which has around 1 billion ash trees.
A joint US Forest Service and Ohio State University study of 457 ash plots in Michigan, Ohio and Pennsylvania found that more than 99% of trees had died within six years of a borer infestation ash.