Beech trees face uncertain future

Loss of tree could impact wildlife species

By Mike Lynch

In June, state workers marking boundary lines in Ferris Lake Wild Forest noticed something awry with the beech trees. The leaves were curled and falling to the ground. 

Beech leaf disease had reached Herkimer County in the Adirondacks. This ailment has the potential to kill off large swaths of American beech trees, whose nuts are a key food source for wildlife. 

First discovered in Ohio in 2012, beech leaf disease has been spreading in New York since at least 2017. As of September, it’s been found in 36 counties statewide, blanketing western New York and moving rapidly through the lower Hudson Valley and Long Island. It’s only been found in one Adirondack location, but it’s been known to spread quickly.

 “I’m told that practically every beech tree in Westchester County has beech leaf disease,” said Maria MoskaLee, a forest health specialist with the state Department of Environmental Conservation.

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In a study of the disease at Kennedy State Forest in Cortland County, DEC forest health scientists found it expanded from about one acre with 190 trees in 2020 to about 4.5 acres with 940 trees the next year. In 2022, it has ballooned to 15 acres and infiltrated isolated forested areas about a mile away.

Although there is no known management strategy to stop the spread, some trees have shown natural resistance and pesticides are being studied. 

The spread is bothersome because the disease can kill native American beech trees and ornamental ones in a few years, with mature trees lasting longer than younger ones. The loss of leaves can be fatal for trees because they provide food and air for the plant through photosynthesis. 

“Trees can usually withstand defoliation for two or three years, but then they start using up all those excess reserves and they die,” said Rebecca Bernacki, terrestrial invasive species coordinator with the Adirondack Park Invasive Plant Program (APIPP). “That seems to be where things are headed with beech leaf disease—that it can kill the trees over time.” 

Unknown origins

Because the disease was recently discovered in the U.S., its biology and vectors aren’t well understood, MoskaLee said. 

Research has shown that the nematode worm, Litylenchus crenatae mccannii, plays a role in spreading the disease, but it’s unknown if it is the sole cause of the damage or if another pathogen, such as a fungus, bacteria or virus, is involved. 

And it’s unclear how it finds the beeches. 

For instance, its first known Adirondack location is away from trails and isn’t a destination. “It was just in the middle of nowhere,” MoskaLee said. 

Some researchers have theorized that birds spread the disease, she said.

To track the disease, DEC conducts surveys throughout the state, including in all of the Adirondack counties. 

The department and APIPP are also asking for help from the public. In September, the two entities partnered on a webinar that was intended as a training session for volunteers in the Adirondacks. 

People are being asked to look for symptoms of the disease on their excursions, photograph the evidence, and file reports on the ImapInvasives app, a tool used by land managers and scientists to track the spread of invasive species. 

Beech bark disease

Complicating the issue are other threats. 

Nova Scotia has been battling the beech leaf-mining weevil for at least a decade. That invasive beetle kills beeches and it may only be a matter of time before it’s found elsewhere. 

“Once these things are out and established in the forest, like this weevil, it’s pretty hard to stop them from spreading,” said Gary Lovett, a forest ecologist with the Cary Institute of Ecosystem Studies. 

But more immediately, mature Adirondack beech trees have been dying since the 1970s after beech bark disease moved into the forests during the previous decade.

That disease occurs when the trees get a fungal infection after beech scale insects damage the bark, allowing the fungus to penetrate. This disrupts the nutrient system, and most trees eventually die. 

The disease kills most trees within 10 years, but some can live with it for decades. 

A study by SUNY College of Environmental Science and Forestry in Newcomb found that trees with trunks greater than 15 inches disappeared from the forest, while those 6 to 15 inches wide maintained a stable population. Plus, the beech tree mast crop increased, producing more beech nuts from 1994 to 2003 than 1988 to 1993.

In addition, impacted beech trees tend to send out shoots, which outcompete other species and create thickets. These areas of dense beech growth are a headache for bushwhackers and backcountry skiers, but they can also harm the forest by reducing the diversity of plant and tree species. 

Impact to wildlife

In the Adirondacks, American beech, sugar maple and yellow birch are the most common tree species in northern hardwood forests which make up more than 50% of forests in the Adirondack region, according to SUNY ESF.

The loss of beeches would have a significant impact on the ecology of the forests. Studies have shown that wildlife thrive after feeding on beech nuts, which come from the bumper crop that generally occurs every couple of years. 

“It’s an excellent food, probably nutritionally the best food in the forest here,” said Stacy McNulty, associate director of research at SUNY ESF.

Black bears, mice and several dozen other species eat the crop. The high protein and fat content is particularly valuable for animals in the fall when they are preparing to hibernate. 

“When we have a really good food year, it actually kind of plays out in sort of like an energy pulse that next year,” McNulty said. 

 By dining on the nuts, black bears have more cubs because they’re able to pack in more calories for the winter before giving birth. Small mammals produce more young, creating prey for predators. 

And when young predators are born into a season when there is more prey, they have a high survival rate because there’s more food available. 

“They call this the silver spoon effect,” said DEC wildlife biologist Paul Jensen.

 A study in Maine showed that after a robust beech mast about 80% of sows produced cubs, Jensen said. In contrast, after a mast failure, only 22% of adult sows produced cubs.

Trapper and hunter harvest numbers also tend to go down during crop years because bears, martens and fishers tend to travel less for food, making them less vulnerable.

What would happen if beech trees disappeared or were greatly reduced in the Central Adirondacks? Jensen said it’s hard to know. Animals would be able to find other sources of food, but perhaps not of the same quality. 

In places, such as the Lake Champlain and Lake George regions, there are oak trees that produce acorns that wildlife can feed on. 

But beeches are the only mast producing tree for wildlife in the Central Adirondacks. One potential replacement is the American chestnut, Jensen said. That tree started disappearing from the landscape around the turn of the 20th century due to a blight. A species that could grow to heights greater than 100 feet and widths of more than 10 feet, its nut fed a wide range of species from birds to bears. 

Today, SUNY ESF and U.S. Forest Service are among those working to restore the species with a blight-resistance form. But native range maps show chestnuts grew throughout the east, but were not as abundant in the northernmost U.S. because they weren’t as cold-tolerant as maples and beech.

Economic ramifications

While the loss of American beech trees could impact wildlife, the economic ramifications wouldn’t be as significant. 

Forestry consultant Tim Burpoe said if this additional disease did cause the demise of beech trees, it wouldn’t cause a “big hole” in the forest product industry. The wood from mature trees is used for items such as pallets and beech makes good paper and firewood. 

“It doesn’t grow up to be a real good forest product,” said Burpoe, who has worked in the industry for several decades. 

As for the syrup industry, producers generally stick with tapping maple trees because it takes less effort. Maple sap has a high sugar content and is easier to extract. Adam Wild, director of Cornell University’s Uihlein Maple Research Forest in Lake Placid, said his organization has been experimenting with making beech syrup, hoping to diversify the industry and create alternatives to maple syrup. However, he said he only knows of one other producer making beech syrup in New York state. “It’s a novelty product,” he said. 

New Leaf Tree Syrups in Lyon Mountain announced in June 2019 it had created the industry’s first ever American beech syrup. 

“Having beech (syrup) adds additional variety to what we can offer from the forest,” New Leaf owner Michael Farrell said. “It’s not a big part of what we do, but we’re glad that we do it.”

But he also noted he’s one of the few maple syrup producers willing to take a chance on the troubled tree. Many other producers look to clear it from their property.

“Beech is kind of a problematic tree species right now for people who produce maple syrup,” he said. 

That’s because healthy beeches are hard to find. Instead most are infected with beech bark disease, which causes them to send out multitudes of suckers (root sprouts), taking over the forest floor and outcompeting sugar maple trees.

“I personally love beech. I mean, I think it’s a great tree. I’ve been in some incredible beech stands in the Midwest,” Farrell said. “It’s a shame what’s happened to it.”