Struggling with blight, American chestnut tree faces new disease identified by Erie County researchers

·7 min read

Erie has a Chestnut Street.

So do the Erie County municipalities of Cranesville and Corry, Girard and Lake City, Edinboro, Waterford and North East.

There’s a reason you find so many stretches of road that carry that name here and elsewhere in the eastern United States. American chestnut trees once numbered into the billions, stretching from Maine to Mississippi.

“The American chestnut was a very plentiful tree, especially in Pennsylvania,” said Sara Fitzsimmons, director of restoration at The American Chestnut Foundation at Penn State University.

The American chestnut was known as a cradle-to-coffin tree because its rot-resistant wood served people’s needs from birth to death. It also produced healthy and tasty nuts eaten by humans and their animals as well as by wildlife.

Then a blight, first officially identified in 1904 in the Bronx Zoo, struck American chestnut trees. They never recovered and are now considered to be “functionally extinct.” New trees sprout, but most don’t live that long. A few old “survivors,” often scarred by the blight, are known to be out there, including in Erie County. And now the American chestnut is facing another challenge, identified by a Penn State Behrend student at a research site in North East Township.

“This was a tree that ... was a major part of the hardwood forest,” said Bryan Hed, a plant pathologist at the Lake Erie Regional Grape Research and Extension Center. “It was a very important tree in the ecosystem.”

Demonstration plot shows signs of blight

Fifteen chestnut trees grow in a single row on center land at the intersection of Route 5 and Cemetery Road in North East. They include five American chestnut trees, five Chinese chestnut trees and five hybrids that are a cross between American and Chinese. The oldest were planted there in 2013. A 21-foot-tall hybrid is currently the biggest.

While the center, part of Penn State’s Agricultural Experiment Station system, works almost exclusively with grapes, Hed said officials wanted to diversify a bit. So they connected with Fitzsimmons and the foundation to add the 15 chestnuts in a demonstration plot that can be used to study the trees and inform people about them.

The chestnut blight has hit the five American trees there. They and a couple of the center’s hybrids also are showing signs of the newer disease, identified there in 2018 by Emily Dobry, a master’s degree candidate in horticulture at Penn State Behrend.

She said the new pathogen, chestnut brown rot, was first documented in Europe about a decade ago. She said it’s been really damaging to younger trees but the harm to more mature trees isn’t clear.

“We don’t know the long-term effects of that because it really hasn’t been studied,” she said. “It’s a pretty new pathogen.”

Although it’s now been found in multiple locations in the United States, research into it is new and ongoing. Among other things, researchers are still trying to determine where it came from or if it’s always been around and something like global climate change has caused it to start damaging trees, Dobry said.

“It appears to be emerging,” she said.

She said the chestnut brown rot wounds on younger trees resemble chestnut blight and could have been misidentified as that previously. Dobry wants to sound the alarm about the new disease.

“We don’t know if the trees can recover at this point,” she added.

Chestnut blight discoveries

The older blight, a fungal pathogen that was accidentally imported with trees from Asia, was identified in the United States in the early 20th century, although it could have arrived here sooner. By the middle of the 20th century, the disease had virtually wiped out the American chestnut tree, which had little to no resistance, Fitzsimmons said. The Chinese chestnut trees are resistant to the blight.

Fitzsimmons said the American trees aren’t extinct because the blight can’t kill the roots. So the trees re-sprout, they grow maybe a dozen or 15 years, get the blight, die, repeat. There are lots of such sprouts out there, Fitzsimmons said. But they’re lowly, more like shrubs than the trees that once could grow over 100 feet in height and live for centuries.

Dobry said that the longer ago an American chestnut tree died, the harder it becomes for it to continue sending up new shoots. She also said that some young American chestnut trees do live long enough to produce nuts and reproduce, but then those new trees face the same blight battle as their predecessors.

A few old survivors do exist, growing on decade after decade despite the blight scarring their trunks. One is said to be in York County. Erie County could have some as well.

Fitzsimmons said there are at least a couple chestnut trees in Erie County that seem to have moderate resistance to the blight.

Pat Chamberlain is an American Chestnut Foundation volunteer from Cussewago Township who is familiar with those trees.

He said there are three trees at one location and one tree at another site, all in Springfield Township, that appear to be survivors. All are located on private property.

The three on the same land are maybe 75 years old, Chamberlain said. The largest reached more than 40 feet tall and is less than 3 feet in diameter. He said it seems “to have a wee bit of Chinese ancestry in it,” and might only be seven-eighths American chestnut.

“It’s a mystery how they got here,” he said.

He doesn’t see evidence of Chinese or Japanese chestnut genes in the other tree, which he thinks is at least 50 years old and about 2 feet in diameter, but it also has been able to fight off the blight, he said.

Researchers still seeking solutions

The American Chestnut Foundation, and others, are still trying to figure out why a very few American chestnut trees have resistance to the blight. That doesn’t mean they’re immune, as survivors show signs of blight, but rather that it causes them less damage and they can survive.

Efforts to combat chestnut blight have included crossbreeding with Chinese chestnut trees, which are resistant to the pathogen. But Hed, from the grape research and extension center, said researchers discovered it’s not a single gene but rather a number of them that are involved in resistance. So one or even two or more crossbreeds haven’t provided a solution.

Researchers are also looking into making the pathogen itself sick by infecting it with a virus, Fitzsimmons said. She said another attempt, which is being reviewed by the Environmental Protection Agency and U.S. Department of Agriculture, would involve creating a genetically modified chestnut. Researchers from the foundation and the State University of New York’s College of Environmental Science & Forestry are looking at adding a gene from wheat to the American chestnut to enhance the tree’s ability to withstand the blight.

The first step to restoring the American chestnut is developing disease resistance, Fitzsimmons said. Next is getting healthy trees back into the woods. While there is hope that can be done, she and Dobry both said it will take time.

“If the trees can be reintroduced to the forests, scientists are fairly optimistic about its recovery,” Dobry said. “The timeline is long, though. It would probably take a century or more to establish large enough populations for man to step back and let nature take over.”

Fitzsimmons said bringing back the American chestnut is about more than one tree and involves restoring the ecosystem.

“Our forests are kind of teetering on a precipice,” she said, adding that ash and hemlock trees also face dangers.

She said restoring the American chestnut tree could help develop a template for saving other trees and add diversity.

“Our forests can only be healthy with diversity,” she said.

Contact Dana Massing at dmassing@timesnews.com. Follow her on Twitter @ETNmassing.

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