ST PAUL, Minnesota — On Thursday, there was still no containment on the fires burning in northeast Minnesota.
They are being fueled by hot, windy conditions, as well as a large number of dead and downed trees. What is killing those trees, however, is a rice grain-sized insect.
The spruce budworm is eating its way through the balsam fir and spruce that make up much of the Northwoods, in what the state’s Department of Natural Resources calls the worst outbreak in decades.
“They’re called budworms because that’s where you’ll kind of find them, in the buds,” said the DNR’s Forest Health Specialist Eric Otto.
The native insect is currently hatching and feasting on the foliage to the point where the trees will die.
“A tree can have thousands of caterpillars and that’s what results in the destruction,” replied Otto.
He claims 700,000 acres have been destroyed in this latest outbreak, which occurs every 30 to 60 years.
“We have more mature balsam fir in the landscape and that kind of starts an outbreak,” Otto explained.
With their thin bark and shallow roots, the trees pose an already significant fire risk. According to Otto, more fires occurred hundreds of years ago, wiping out balsam fir and spruce. Logging also eliminated more resilient trees, such as red and white pine, making it more difficult to reestablish those species.
The impacted land is also a patchwork of ownership, complicating problem management.
“A lot of it is federal forest service, the state, county and a lot of private land owners if you wanted to do any prescribed burning or different types of management,” according to Otto.
Otto believes that reducing the risk requires increasing tree diversity and making the landscape more resilient for when the budworm returns.
The larvae will eventually develop into moths and lay more eggs later this summer.
“They won’t do any feeding damage,” Otto said. “They basically just look for a site to over winter, usually under the bark.”
When the cycle begins again next spring, the budworm can kill a tree in as little as five years. And it’s those dead and downed trees that officials say are now fueling the area’s latest fire.
“There’s a heavy dead component due to budworm,” Incident Commander Ryan Williams stated in a press briefing on Tuesday. “There’s a lot of receptive fuels everywhere.”
If you notice budworm populations in balsam fir stands, experts recommend harvesting them as soon as possible to preserve their value.