Drive around Vermont and you may notice that Eastern white pine trees have been turning shades of yellow and brown and shedding new needle growth.
But the trees aren’t dying, said Savannah Ferreira, the forest health specialist for the Vermont Department of Forests, Parks and Recreation. They’re sick with white pine needle disease, which causes trees to lose needles infected with fungi.
“Otherwise healthy trees are likely to recover from this. So although it does look really alarming now, once these needles drop, hopefully we’ll get another reflush of green needles, and it will look better for the rest of the growing season,” Ferreira said.
White pine needle disease is caused by fungal pathogens that thrive in wet, humid conditions, according to Ferreira. Just like mold grows in the most humid corners of a house, the fungi that cause the disease can spread quickly if the crowns of pine trees retain moisture over time.
With historic rainfall across Vermont last spring and summer, Ferreira said, fungal spores had an ideal environment to reproduce and attach to emerging pine needles. Those needles, which have grown with the disease throughout the year, are now displaying the yellow and brown hues the disease is recognized by.
And locals are starting to notice. Mike Clifford, a Killington resident, said he was concerned to see brown trees cover the hillsides along routes 107 and 4 — largely because he’s never seen anything like it before.
“It’s pretty noticeable. You see all green trees, and then all of a sudden, this big clump of brown ones,” Clifford said. “It just seemed strange. … There seem to be an awful lot of these sick trees.”
Ferreira said that while most reports she’s received are coming from southern Vermont, the disease is prevalent not only statewide but also across the Northeast. She said her team will conduct aerial surveying in late June or early July to measure the scope of the problem, but there is no current estimate of the extent of the damage.
In the meantime, Ferreira said locals can help limit the spread of the disease by not moving plant material, such as firewood, to new areas. There is no need to cut down trees that look sick, she said, because trees that are otherwise healthy should make a full recovery once they shed their infected needles. The fungi that causes the disease is not considered harmful for animals or humans, Ferreira said.
The true concern, she said, is whether or not the widespread damage being observed now will become an annual pattern.
“If we do get successive years of severe symptoms, it can cause stress (on trees) and, over time, that can definitely exacerbate other symptoms and lead to mortality,” Ferriera said.
Eastern white pines grow in forests throughout Canada and the Northeastern and Middle Atlantic United States, but New England’s changing climate — specifically, its increased spring temperatures and precipitation levels — has created conditions that are the most conducive for the spread of the disease, according to a 2019 report by the University of Massachusetts Amherst. Repeated cycles of infection can “severely weaken trees” and lead to their deaths, according to the report.
Other than thinning out white pine groves to slow rates of infection and providing nitrogen fertilization to help infected trees recover, the study found that little can be done to stop the disease because of pines’ “natural abundance and large size.”
Staff at the Department of Forests, Parks and Recreation have been monitoring the disease since 2010, when “widespread white pine needle damage developed suddenly,” according to the department’s annual Forest, Insect and Disease Conditions report.
Since then, white pine needle disease has caused different levels of damage from year to year — all depending on the preceding spring’s weather conditions, which determine if fungi will latch on to new needle growth.
According to the 2023 report, the disease caused 3,349 acres of observable damage last year, largely concentrated in Windsor and Orange counties. Ferreira said she expects this year’s damage will be worse.
As recently as 2016, damage has been “widespread and severe” in more than 30,000 acres of pines, according to the department’s annual report.
For now, Ferreira said all she can do is wait for trees to grow new, healthy needles and cross her fingers that the disease won’t hit Vermont as hard next year.
“It definitely hasn’t been as wet as it was last year,” she said. “So I’m staying hopeful that, next year, our trees might be able to rebound a little better.”
Read the story on VTDigger here: Vermont’s brown pine trees aren’t dead. They’re just a little sick..