It was inNew YorkCity that a mysterious fungus was first spotted on an American chestnut, a blight that was to rapidly sweep across the eastern US, wiping out billions of the cherished trees. Now, 120 years later, there is fresh hope of a comeback for chestnuts, spurred not only by scientists but also eager New Yorkers planting blight-proof seeds in their back yards and local parks.
The American chestnut wasonce found in vast numbersfrom Maine to Mississippi and known as the redwoods of the east due to its prodigious size. But 4bn trees were killed off in the first half of last century by a blight introduced from Asia to which it had little defense, spread by spores carried by the wind, rain and animals.
The blight,Cryphonectria parasitica, first spotted in 1904 on trees at New York’s Bronx Zoo, causes necrotic lesions on the chestnut’s bark as it cuts off the tree’s access to water and nutrients until it dies above ground.
Some chestnut roots and shoots remain today, but very few trees reach their full imposing extent, of around 100ft in height and 8ft wide at the base. Decades of scientific and charitable work has sought to resurrect the chestnut, with varying results, and now a new project is turning to the citizens of New York to help restore the species to something of its former glory.
New Yorkers have been invited to apply for and plant around 400 chestnut saplings tended to by theNew York Restoration Project(NYRP), a non-profit group that was founded by the actress Bette Midler, in the hope that chestnuts can spread across the city in a new urban forest and eventually again thrive across the US east.
“The interest has surprised us, this has really touched a nerve,” said Jason Smith, director of north Manhattan parks at NYRP, about the response from a crowded city not typically associated with available green space and expansive back yards. Plantings require sunlight and must avoid areas under power lines but chestnuts can take hold in smaller gardens and, after five years or so, produce a prodigious bounty of tasty nuts.
“We’ve had requests for many thousands of trees, more than the seeds we have,” Smith said. “I’m sure a lot of people have applied and don’t really have the room, so there’s an educational component there.”
“But the goal is to get as many potentially disease-resistant trees growing as possible and people can do something directly about that,” Smith added. “When you talk to folks, they really do care about biodiversity loss, they just don’t think they can do anything about it. Here, they can.”
Project leadersare aiming for 1,000 chestnuts in New Yorkbut have to content themselves with a smaller initial number due to a constrained availability of seeds, garnered from plantings by theAmerican Chestnut Foundationand also from the 230 or so chestnuts that remain scattered in New York itself. The saplings grown from this group are huddled in pots in a fenced off area in Manhattan and will soon be distributed to successful applicants.
Around half of New York’s surviving chestnuts are found in a promising initiative that has taken root in Highbridge Park, a strip of woodland in the upper reaches of Manhattan that slopes down towards the Harlem river.
The New York Restoration Project started work here in the 1990s, a time when the area was a derelict dumping ground for car parts. In typical New York fashion the task of coaxing back an ecosystem has faced a myriad of unusual challenges – from battling invasive knotweed to dealing with a homeless encampment and even a group of resident nudists.
“There has always been something to keep us busy,” said Smith. His group has installedrain gardens, to help stem the flooding risk from the nearby river, removed debris and is in the process of installing a new path to allow locals to enjoy the revitalized park again. On a recent warm spring day, a single rusting car engine sat, like a museum piece, amid a verdant throng of ash, sycamore and sugar maple. Spores from cottonwoods covered the ground like a downy blanket.
The crowing glory of this space, though, is its American chestnuts, planted in 2017 to stunning success. “We didn’t know what was going to happen but this tree here is probably like 35ft tall now,” said Smith, pointing to a chestnut that pierced the thin canopy. The blight still might take hold here but there has been remarkable resilience so far with just two of the more than 120 trees – which are hybrids with a Chinese chestnut variant but still genetically 95% American – struck down by the disease.
“We have an opportunity to have a distributed, community-based breeding effort in a way where we’re giving all these seeds to people, asking them to track them, and hoping that some of them will prove to be very disease-resistant and largely American,” said Smith.
The mass citizen science effort will, it’s hoped, enlarge the pool of immune trees that, over the years, should steadily repopulate forests that have been decimated of chestnuts. The wellspring of healthy trees is still frustratingly small, only 2,000 or so across the eastern US, according to Sara Fern Fitzsimmons, chief conservation officer of the American Chestnut Foundation, meaning that restoration this way will be arduous.
“There aren’t enough trees for high-scale restoration but we can breed them together to make them even more resistant,” Fitzsimmons said. “We keep making incremental progress.”
A few years ago, it was hoped that this attritional warfare could be surpassed by a sort of super weapon in the form of genetic modification. A new type of chestnut, with a wheat gene inserted into its genetic makeup, showed remarkably favorable signs of survival in the lab but then floundered when planted in the field.
The chestnut foundation cut support for the project, called Darling 58,in 2023. Despite this, the genetically engineered variant’s creators at the State University of New York are pushing ahead, with the US Department of Agriculture (USDA)consideringwhether it should be deregulated and allowed to be commercially spread, to the alarm of some environmentalists.
“This isn’t a restoration project, it’s a genetically flawed science experiment poised for commercialization at the expense of our forests,” said Anne Petermann, co-founder of Global Justice Ecology Project. “We are appalled that the USDA is seriously considering approving this risky GE tree when they know it is based on ten years of flawed research and has exhibited severe problems in controlled field tests.
“The forests deserve real science, not flawed experiments. The American chestnut deserves restoration, not commodification.”
There is other work, too, going on try to give the fungus itself a disease but for now hope is mainly resting on the toil of hybrids and replanting as a path back for chestnuts. “We all thought genetic modification would be a game changer that would revolutionize American chestnut restoration,” said Fitzsimmons.
“We still see promise in it, but it won’t be a silver bullet. Instead of a singular product we need to do a diversity of things to not only restore chestnuts but also help other species like ash and hemlock that are under threat.”
The tenacious attempts to revive chestnuts stems, in part, from a desire to atone for an environmentally ruinous era of American expansionism that, among other things, also wiped out thepassenger pigeonand almost killed off all the country’sbison. Fitzsimmons said that her family is from Appalachia, where the chestnut is still venerated as a versatile, fast-growing tree that supplies delicious nuts.
“You can use the wood for anything, it’s a cradle to grave tree because you can use it for cradles or coffins, you can fatten your hogs on the nuts,” she said. “I’ve heard it referred to as charismatic mega flora – people are just drawn to it. We have had the ecological tragedy of losing it but it’s also a cultural tragedy. We want to restore those cultural connections.”
This restoration could take decades, though. “We should think of it as a cathedral building undertaking that will maybe not be complete in our lifetime,” as Smith put it.
But at a time when the de-extinction of lost species, such as thewooly mammothordire wolf, is in vogue in an attention-grabbing way, the return of the chestnut has a more pragmatic rationale, its proponents argue.
The tree can soak up vast quantities of carbon,vital amid the climate crisis, and fulfills all of the same roles for insects and birds even if it is crossed with a Chinese or Japanese variant.
“This isn’t a gimmick, we are thinking about the ecological function of the tree,” said Smith. “At a time when we are losing so much of our forests, we can’t be purest about bringing back the most important tree in the northeast. We usually aim really low for conservation efforts in urban spaces, and we don’t have to.”