Bronx Zoo Brings Back the American Chestnut

The Bronx Zoo Brings Back the American Chestnut this month, more than 120 years after the tree-killing blight that wiped out nearly 4 billion of them was first documented on the zoo's own grounds. In early October 2026, the zoo and the New York Restoration Project planted a gift of 25 hybrid saplings bred to resist that same fungus, placing the young trees at three sites across the campus, including the riverwalk and the Bronx River's east bank.

The symbolism is hard to miss. In 1904, the institution's chief forester, Hermann Merkel, became the first person on record to describe the orange cankers creeping across chestnut bark. The fungus, likely carried on imported East Asian trees, then raced across the East Coast and inland, and by the 1950s virtually every native chestnut was dead. A canopy giant that once stretched from Ontario to Mississippi, prized for its timber and its dependable nut crop for wildlife, the American chestnut is now considered functionally extinct in the wild, according to the Wildlife Conservation Society's announcement.

The newcomers come from NYRP, the citywide conservancy leading New York's urban chestnut comeback, in partnership with The American Chestnut Foundation. Since 2017, the group has planted and tended more than 200 hybrids in Highbridge Park in northern Manhattan, some now topping 40 feet and bearing flowers and nuts — living proof that the species can thrive in city soil, as reported by Times Now World.

As the Bronx Zoo Brings Back the American Chestnut, its leaders are framing the planting as both ecology and heritage. In a statement, zoo director Craig Piper described the campus as an iconic green space the institution has kept forested "for the enjoyment of generations of New Yorkers," saying the work supports local wildlife as well as the animals in its care, according to blooloop. NYRP executive director Lynn Bodnar Kelly called the project "an act of restoration" and "an invitation" to reimagine what the city's landscape could become.

Bronx Zoo Brings Back the American Chestnut: A 122-Year Timeline

Here is how the Bronx Zoo Brings Back the American Chestnut as part of a century-long arc of loss and recovery:

• 1904: Chief Forester Hermann Merkel documents the orange cankers of chestnut blight at the zoo — the first official record of the disaster.
• 1904–1950s: The fungus sweeps the chestnut's native range; by mid-century, billions of trees are dead and the species is functionally extinct in the wild.
• 2017: NYRP begins planting hybrids at its Highbridge grove, building the city's largest chestnut grove.
• 2025: The group launches the 1,000 Chestnut Challenge, distributing hundreds of saplings to city residents.
• September 2026: Federal regulators clear a bioengineered blight-resistant chestnut, a separate rescue strategy.
• October 5, 2026: The zoo plants its new grove — closing the loop at the place where the blight was first recorded.

The Bronx Zoo Brings Back the American Chestnut through classic breeding, but that is not the only strategy scientists are pursuing.

Hybrid Breeding vs. Bioengineering: Two Roads Back

The way the Bronx Zoo Brings Back the American Chestnut is deliberately low-tech: decades of crossbreeding American trees with blight-resistant Chinese varieties, then repeated backcrossing and genomic screening to keep the American character while borrowing resistance. Because they are conventionally bred, these hybrids need no federal approval before planting, as reported by Reason.

The rival approach is genetic engineering. The Darling 54, developed at SUNY's College of Environmental Science and Forestry, carries a wheat gene that produces oxalate oxidase, an enzyme that breaks down the fungal toxin. In September 2026, the U.S. Department of Agriculture decided the tree poses no greater plant-pest risk than a conventional chestnut and deregulated it — a first for an organism engineered for ecological restoration, according to Reason. Release to the public still awaits approval from the Environmental Protection Agency.

Not every researcher is convinced the lab-built tree will thrive. In 2023, the foundation — which had initially cheered the engineering project — withdrew its support, saying the inserted gene disrupted another gene and left the trees growing and surviving more poorly than conventional ones. The foundation also argues the modified trees have not been tested long enough to prove their resistance holds up over decades. Its director of science, Jared Westbrook, said the group backs "any genetic technologies that will be effective" at restoring resistance but fears a high-profile failure would energize anti-biotech campaigns against future engineered trees.

How New Yorkers Can Join the Comeback

The Bronx Zoo Brings Back the American Chestnut at a moment when the effort is going citywide. Through the challenge, NYRP has already distributed more than 350 saplings to residents across the five boroughs this year and plans to plant at least 500 more in the coming year. Readers who want in can join the distribution list through NYRP — or simply visit the zoo's new grove, which the zoo says it will expand if the first trees thrive.

For more urban-nature coverage, explore our Plants and Trees section, and see how young people are fighting for a livable planet in Climate Emergency.