Across Connecticut, once-lush beech trees are dying
Last year, when John Lucak took his daily, fourmile walk in Waveny Park in New Canaan, the world was green and beautiful.
This year, not so lush. The 300-acre park has groves of near-defoliated beech trees with stunted, ruined leaves.
“They look horrible,” Lucak said.
Welcome to beech leaf disease, and a world where one of the most important trees in our forests may go the way of the American chestnut — lost in a decade or two.
It’s not just in New Canaan.
Geordie Elkins, operations manager at Highstead, the arboretum and land conservation organization in Redding, said he’s seen beech leaf disease there for the first time this year.
Far to the north, at Great Mountain Forest, whose 6,000 acres straddles Norfolk and Falls Village in Litchfield County, forester Jody Bronson found the disease in a stand of beech trees deep in the woods.
“This is a place that’s miles from any road,” Bronson said.
“It’s everywhere,” said Robert Marra, an associate scientist in the Department of Plant Pathology and Ecology at the Connecticut Agricultural Experiment Station in New Haven, which identified the disease in Connecticut in 2019.
This news is the latest in a bad run for the natural world in the state.
In 2008, state bats started dying at an alarming rate because of a European fungus that worked its way into their winter hibernation quarters. Now, most species of cave-dwelling bats are on the state’s endangered species list.
In 2012, the emerald ash borer — an invasive shiny green beetle from Asia — showed up in the state. Now, a decade later, it has decimated nearly all the state’s ash trees.
”What’s next?” Marra said.
Scientists say beech leaf disease is caused by a nematode — Litylenchus crenatae mccannii — native to Japan, Korea and Southeast Asia.
Researchers identified it in Ohio in 2012. It has since spread to nine other states — Connecticut, Rhode Island, Massachusetts, Maine, New York, New Jersey, Pennsylvania, West Virginia and Virginia — and the Canadian province of Ontario.
The nematode — a microscopic roundworm — works its way into the overwintering buds of beech trees, then feeds on the buds and the emerging leaves. The new leaves emerge dry and brittle, marked with a distinctive pattern of dark stripes. They fall prematurely, leaving the tree leafless and unable to function. The disease can kill a young tree in two or three years and a mature tree in six.
Marra said because the nematodes are so tiny, people can’t just look at what they think is a healthy leaf and see them. Nor, looking at the entire canopy of a mature beech, can they pick out the few leaves where the nematodes might be setting up shop.
So, when people see stunted, striped beech leaves, he said, that means the nematodes arrived a year or two before.
Marra said no one knows exactly how the disease is spreading. But a bird, perching on the wet leaves of an infected beech, could easily pick up the nematodes, he said, and spread them to other trees. People may be unknowingly buying infected nursery stock and
spreading the nematodes, as well.
The tree under attack — the American beech — is it’s one of the most important species of trees in the eastern forests of the United States.
It’s a tree whose nuts feed birds and mammals of all sorts — everything from squirrels and chipmunks to wild turkey, white-tailed deer and black bears. Nationally, it’s a host to 120 species of butterflies and moths. Birds feed on the insects beech trees attract. Beeches can provide cavities for a variety of tree nesters.
Its saplings are shadetolerant. They can hang on in the woods for years, until some natural event creates a
clearing in the woods. Then, beech trees can grow 50 to 80 feet tall and live for hundreds of years, feeding and sheltering hundreds of generations of forest dwellers.
Marra said it’s important for scientists to learn as much as they can about beech leaf disease as quickly as possible.
It’s a difficult task, studying an emerging plant disease only on the scene for a decade — and in Connecticut for a few years — caused by a microscopic roundworm that people don’t detect until it’s too late.
“It’s just not good,” Marra said.