Before the arrival of chestnut blight, American chestnuts towered over eastern forests from Maine to Mississippi. This deciduous species accounted for 25 percent or more of some forests’ trees. Estimates place the preblight population of American chestnuts at approximately 4 billion trees.
Then, sometime in the late 1800s or early 1900s, disaster struck. The fungus that causes chestnut blight—Cryphonectria parasitica—arrived on American soil, likely on nursery stock from China or Japan. By 1940, blight had brought down nearly every mature chestnut tree in the country. The once-dominant American chestnut seemed all but extinct.
Yet some trees survived—crippled and diminished by the blight, but alive. After decades of selectively breeding these remnant American chestnuts with blight-resistant Chinese chestnuts, The American Chestnut Foundation (TACF) produced a hybrid chestnut that may be the best hope yet for the species. Because of repeated backcrosses with American chestnuts, only 1⁄16 of the hybrid’s genetic material comes from the Asian species. TACF hopes that the hybrid tree—known as the Restoration Chestnut 1.0—will combine the American chestnut’s forest-type growth, rot-resistant wood, and prodigious nut production with the Chinese chestnut’s blight resistance.
“These seeds are considered ‘potentially blight-resistant,’” says Mila Kirkland, TACF communications director. Of the oldest Restoration Chestnut 1.0 trees, planted in 2008, Kirkland reports that approximately 16 percent show high resistance to blight, while 50 percent show moderate resistance. By selectively breeding the individuals that show the greatest resistance to blight, TACF may eventually produce a chestnut capable of restoring the species to its prior glory.
Once TACF has bred a tree that shows consistent high resistance to chestnut blight, it will begin offering seeds and saplings to the general public. Until then, would-be chestnut growers can acquire Restoration Chestnut 1.0 seeds through TACF annual sponsorship (starting at $300 for access to four seeds; acf.org/seeds_seedlings.php).
“Since these seeds are still being tested, they are only available on a limited basis to sponsor-level and above members,” says Jack LaMonica, president of TACF Virginia Chapter. He advises planting chestnuts in sunny, well-drained sites with acidic soil. Before receiving any seeds, TACF sponsors must agree that the chestnuts are for testing and evaluation only, explains LaMonica. “Our primary goal is to restore chestnuts to the forest.”
Originally published in Organic Gardening magazine, December 2013/January 2014
Photo courtesy of the Forest History Society via the American Chestnut Foundation