From PBS Terra.

We used to have BILLIONS of these extraordinary trees. Thanks to a tragic twist of fate, now… there are only 4.

Once towering over eastern U.S. forests, billions of American chestnut trees nourished ecosystems, built homes, and sustained Appalachian communities. But in the early 1900s, a foreign fungus arrived, and within decades, nearly all of them were gone.

However, the species never fully vanished. Its roots still survive underground, sending up sprouts that grow, die, and regrow in an endless cycle. These trees are biologically alive, but with most never reaching maturity, they remain functionally extinct.

In the forests of Pennsylvania, Shane Campbell-Staton joins Sara Fern Fitzsimmons from The American Chestnut Foundation to track this tree’s strange afterlife and learn the science behind its potential revival. With the help of rare surviving trees, selective breeding, and even gene editing, scientists and volunteers are working to breed blight-resistant trees.

The chestnut’s comeback will take time. But researchers are making steady progress towards developing American chestnut trees that survive and thrive in the native range they formerly dominated.

Learn more about Human Footprint: https://www.pbs.org/show/human-footprint

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