The American chestnut was a dominant tree in the forest of the Eastern US, making up about 25 percent of the hardwood canopy in some eastern forests. Chestnut blight was was accidentally introduced to North America from Asia, through imported chestnut wood or trees in the early 20th century, and by the middle of the century almost 4 billion chestnut trees had dwindled to a few hundred, transforming the USA’s eastern broadleaf forests.
Former range of American Chestnut. From American Chestnut Foundation
Currently, by crossing surving American trees with blight resistant Chinese chestnuts, volunteers have created trees that are genetically mostly American chestnut, but are also resistant to blight.
Juliet Eilperin writes in the Washington Post about The mighty American chestnut tree, poised for a comeback:
The foundation has roughly 75,000 “mother” and “father” trees in 300 volunteer-run breeding orchards across the United States, including 15,000 in Maryland. Saplings and nuts from these orchards are distributed for plantings. The group is cultivating different trees in separate states and continues to cross-breed, volunteer John Bradfield said, “to bring in the diversity that geography brings to a species.”
Now that they’ve got trees with a shot at survival, volunteers have joined federal officials to begin reforestation. They’ve planted 20,000 to 25,000 chestnuts, and some of the most promising work is being done on land decimated by strip mining that must be restored under federal law.
“Surface mines may make the best springboard for the American chestnut back into the Eastern forest,” said Patrick Angel, a senior forester at the Office of Surface Mining who is helping to oversee the effort. “The natural range of the American chestnut and the Appalachian coal fields overlap perfectly.”
There are three-quarters to a million acres of abandoned mining land between Pennsylvania and Alabama that could be reforested with chestnuts and other hardwoods, Angel said. “That’s a huge amount of non-forested land in an area that used to be contiguous forest,” he said.
Below is a video from the US Forest Service about experimental American Chestnut replanting in the wild: