6 days Ago By Melina Walling, Associated Press
It’s been a very long time since vendors sold the American chestnut on city sidewalks. It’s no longer the variety whose smell some people associate with Christmastime as it wafts from street carts. Because it’s virtually extinct.
But memories of the American chestnut’s legacy keep resurfacing for the researchers who want to bring it back. They describe its wood that paneled the homes and schoolrooms of their grandparents, or the photographs of men on the street corners of old Baltimore, with hot bags of nuts cooked on charcoal. “You can feel that connection to a place, and that connection to utility, and the connection to the importance that this tree played in virtually every aspect of the lives of people,” said Sara Fern Fitzsimmons, chief conservation officer with The American Chestnut Foundation, which is working to restore the tree to flourish as it once did.
Fitzsimmons said that will likely take a lot longer than many chestnut enthusiasts had hoped. Researchers have hit roadblocks in attempts to breed or genetically modify a version that can withstand the invasive blight that has hammered the species since the early 1900s. If they find the right variety, they’ll need to figure out how to plant it and help it thrive amid climate change, globalization and development.
Once a hallmark of forests from Georgia to New England, American chestnuts now exist mostly as a vast network of root systems underground, sending up shoots. They grow for a time, but the fungal blight takes hold when the trees start maturing. East Asian varieties, like those that introduced the blight in the first place, are immune to the blight and produce most of the edible chestnuts for fall and winter snacking.
Still, American chestnut trees are better suited for timber, they’re culturally loved all over North America, and they used to be an important species for the ecological health of forests, providing a reliable source of nutritious food and shelter for wildlife and humans. “It was really a pretty significant species to lose,” said Amy Brunner, an associate professor at Virginia Tech who works on the tree’s genetics. “The more diversity you lose, the less resilient that forest ecosystem is.
” The American Chestnut Foundation, among others, has been trying for decades to breed a hybrid that is mostly American in genetics but with the fungus-fighting traits of the Chinese type. Fitzsimmons said breeders have learned just how difficult that is: Blight resistance involves several different genes, and it has proven hard to separate them from the traits that distinguish Chinese chestnuts. To speed the process, some scientists have been working on genetically modifying American chestnuts to see if they can boost their immunity that way instead.
But progress was delayed by a recent mix-up involving two versions of a genetically modified American chestnut that scientists at State University of New York had hoped could get through the regulatory process as soon as this year. “Now it’s taking a little bit longer than we had hoped,” said Linda McGuigan, a research support specialist at the university..
