In the late 19th century, a fungus arriving with Asian nursery stock and timber wiped out roughly four billion American chestnut trees within decades. Once the most abundant hardwood of the eastern United States—feeding bears, turkeys, and generations of mountain farm families—the species now rarely reproduces in the wild, a textbook case of functional extinction: sprouts persist, but the forest is gone. On a recent NPR broadcast, Andrew Newhouse, a biologist leading the restoration effort, discussed where the tree's revival stands.
37 Years of the Revival Project
The project began in 1989 at SUNY College of Environmental Science and Forestry, started by William Powell and Charles Maynard, who devoted much of their careers to it. The strategy was to give the American chestnut an imported armor gene: an oxalate oxidase (OxO) gene borrowed from wheat, enabling the tree to break down the oxalic acid the blight fungus uses as its siege weapon.
Newhouse corrected a common misconception on air, in essence: *the gene we use comes from wheat, and it isn't really resistance—more accurately, it helps the tree tolerate the blight.* The distinction matters. The fungus isn't killed; its chemical weapon is defused. Tree and fungus coexist, and the tree lives.
- Late 19th century: the blight fungus arrives with nursery stock and timber
- Following half-century: ~4 billion American chestnuts die
- 1989: SUNY ESF launches the restoration project
- January 2020: deregulation petition submitted to USDA
- Late 2022: federal draft risk assessment finds low risk
- December 2023: TACF withdraws support for the Darling lines
- September 2026: NPR revisits the project; APHIS has cleared it, EPA undecided
- USDA-APHIS: has concluded Darling 54 is unlikely to pose greater plant pest risk than ordinary American chestnuts and no longer regulates it as a pest—but the foundation notes this is only one of three gates.
- EPA: because the target gene addresses a pathogen, the tree is reviewed under pesticide rules—a "pesticide" that kills no fungus; an exemption is being sought.
- FDA: voluntary review completed, with nutrient analysis showing the nuts are like ordinary American chestnuts—no wheat allergens, no gluten.
A Labeling Mix-Up and the Loss of a Founder
The project stumbled late. Trees distributed to the public were labeled Darling 58 but were actually Darling 54. Line 54 carried harder problems: the inserted construct disrupted a known gene and caused a large deletion; worse, offspring inheriting two copies of the OxO gene (a quarter of progeny) mostly died as embryos. In December 2023, The American Chestnut Foundation withdrew support for the entire Darling line. In November of that year, co-founder Powell passed away. The project's two hardest years fell exactly when it seemed closest to the finish line.
There is a bitter irony: four billion trees died from a fungus, and the rescue project nearly died from a gene inserted in the wrong place. Biology isn't code—there's no line number to roll back to.
Where It's Stuck Now
The blight arrived 122 years ago; two biologists took on the job 37 years ago; now half the doors are open. NPR's interview offered no timeline—Newhouse himself said how long each agency will take is unpredictable.
One more thing worth knowing: genetic engineering was never the only path in this restoration. The foundation's roster lists a three-legged approach—traditional hybrid breeding, biotechnology, and biological control. Tens of thousands of hybrid chestnuts already grow in conservation orchards, backcrossed generation by generation with blight-resistant Asian relatives to select offspring that look American yet resist the blight. Transgenic material is only the sharpest and rockiest blade among them. Whether chestnuts falling on the forest floor will be heard again on these ridges depends not on one lab, but on paperwork moving through several federal offices. Slow—but the doors are opening.