Vermont’s brown pines aren’t dead. They’re just a little sick.

As you drive through Vermont, you will notice the white pines turning yellow and brown and losing their needles.

But the trees aren’t dying, says Savannah Ferreira, a forest health specialist with the Vermont Department of Forests, Parks and Recreation. They’re suffering from white pine needle disease, which causes the trees to lose fungus-infected needles.

“Otherwise healthy trees are likely to recover from this. Even though it looks really concerning now, hopefully once the needles fall off we will get green needles again and things 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, moist conditions, according to Ferreira. Just as mold grows in the dampest corners of a home, the fungi that cause the disease can spread quickly when the crowns of pine trees retain moisture for long periods of time.

Ferreira said historic rains across Vermont last spring and summer provided an ideal environment for fungal spores to multiply and attach to newly emerging pine needles. Those needles, which have grown with the disease all year, now exhibit the yellow and brown hues that identify the disease.

And locals are starting to notice. Mike Clifford, a Killington resident, said he was concerned when he saw brown trees covering the hillsides along Routes 107 and 4 — especially because he’d never seen anything like it before.

“It’s pretty striking. You see all green trees and then all of a sudden you see this big cluster of brown trees,” Clifford said. “It just seemed odd to me. … There seem to be a lot of these diseased trees.”

Ferreira said most of the reports she has received have come from southern Vermont, but the disease is widespread not only nationwide but also in the Northeast. She said her team will conduct an aerial survey in late June or early July to measure the extent of the problem, but there is currently no estimate of the extent of the damage.

In the meantime, Ferreira said locals can help contain the spread of the disease by not bringing plant material such as firewood into new areas. There is no need to cut down diseased-looking trees, she said, because otherwise healthy trees should fully recover once they shed their infected needles. The fungus that causes the disease is not considered harmful to animals or humans, Ferreira said.

The real concern is whether the widespread damage currently being seen will become an annual pattern, she said.

“If severe symptoms occur several years in a row, it can cause stress (to the trees), which can definitely worsen other symptoms over time and lead to death,” Ferriera said.

Eastern white pines grow in forests across Canada and in the Northeast and Mid-Atlantic U.S., but according to a 2019 report from the University of Massachusetts Amherst, New England’s changing climate – particularly higher spring temperatures and rainfall – has created conditions conducive to the spread of the disease. Repeated cycles of infection can “severely weaken trees” and lead to their death, according to the report.

Other than thinning Weymouth pine forests to slow the rate of infection and applying nitrogen fertilization to help infected trees recover, little could be done to stop the disease due to the pines’ “natural abundance and size,” according to the study.

Department of Forests, Parks and Recreation officials have been monitoring the disease since 2010, when “large-scale damage from white pine needles suddenly appeared,” according to the department’s annual report on forest, insect and disease conditions.

Since then, the Weymouth pine needle disease has caused varying degrees of damage from year to year – all depending on the weather conditions in the previous spring, which determine whether fungi attach themselves to the new needle shoots.

According to the 2023 report, the disease caused visible damage on 3,349 acres last year, mostly in Windsor and Orange counties. Ferreira expects the damage to be even greater this year.

As recently as 2016, according to the agency’s annual report, “widespread and severe” damage occurred across more than 30,000 acres of pine forest.

For now, all she can do is wait for the trees to grow new, healthy needles and keep her fingers crossed that the disease won’t hit Vermont as hard next year, Ferreira said.

“It definitely wasn’t as wet as last year,” she said. “So I’m hoping our trees might recover a little better next year.”