For over a century, the American elm (Ulmus americana) has been a ghost in its own landscape. Once the defining silhouette of American town squares, river valleys, and the grand avenues of the Northeast, the species was decimated by the arrival of Dutch elm disease (DED) in the early 20th century. Now, in a quiet, 28-acre grove in southern Vermont, a team of scientists is engaged in a high-stakes, ethically complex project: intentionally infecting thousands of young elms with the very fungus that wiped out their ancestors.
It is a paradox of conservation—to save the species, they must first subject it to a lethal trial by fire.
The Ritual of Infection: A Necessary Cruelty
The project, spearheaded by The Nature Conservancy (TNC) and the U.S. Forest Service, represents the most rigorous attempt yet to restore the American elm. On a spring morning in 2026, Gus Goodwin, TNC’s director of science and technology advancement in Vermont, knelt before a sapling. Dressed in fieldwork gear, he used a drill to create a one-inch-deep wound in the tree’s trunk. Into this breach, he injected a blue pipette containing approximately 100,000 spores of Ophiostoma novo-ulmi, the fungus responsible for DED.
"We need to create a wound," Goodwin said, the whir of the drill punctuating the silence of the grove. "That’s it. Pretty simple."
The goal is to test the genetic resilience of 5,300 elms. Most will die, succumbing to the pathogen that has claimed tens of millions of their predecessors. However, the survivors—those that demonstrate a natural, inherited tolerance to the fungus—will become the progenitors of a new, restored population. By monitoring their physiological responses, researchers hope to identify "super trees" that can be cloned and planted across the landscape, effectively bringing the elm back from the brink of functional extinction.
A Chronology of a Botanical Catastrophe
The decline of the American elm is a cautionary tale of ecological vulnerability and human intervention.
- 1910–1922: DED is first observed in Europe. Scientists in the Netherlands identify the pathogen, which likely originated in Asia.
- 1930s: The fungus arrives in North America, transported on logs intended for veneer. Native elm bark beetles act as the primary vectors, carrying the spores on their bodies as they feed.
- 1935: President Franklin Delano Roosevelt authorizes $2.5 million for an emergency culling program. Unfortunately, the strategy of removing infected trees—without first severing underground root grafts—unintentionally accelerates the disease’s spread, as the fungus travels through the interconnected root systems of neighboring trees.
- 1940s–1970s: A more virulent strain, Ophiostoma novo-ulmi, sweeps through the U.S. By the 1970s, cities like Minneapolis are losing 20,000 elms annually. The "Elm City" of New Haven, Connecticut, is largely stripped of its namesake canopy.
- 1990s–2010s: Early breeding programs by scientists like Alden "Denny" Townsend yield the "Valley Forge" and "New Harmony" cultivars. While resistant, these strains are limited in genetic diversity, leading to concerns about monoculture risks.
- 2026: The Benson, Vermont, project launches, utilizing a broader genetic base collected from "survivor trees" identified across New England.
The Ecological and Cultural Stakes
The loss of the American elm is not merely an aesthetic tragedy; it is an ecological rupture. The species is a foundational pillar for biodiversity. Creatures like the double-toothed prominent moth have evolved specifically to mimic the serrated edges of elm leaves. When the trees disappear, these specialized species lose their camouflage and their host, effectively pulling the rug out from under the local food web.
Furthermore, the American elm is a "hydrological workhorse." It thrives in floodplains, acting as a massive, living sponge that mitigates the impact of the increasingly frequent, climate-driven deluge events seen across New England. Studies suggest that restoring these floodplains could save up to $1 billion in property damage over the next century.
"There’s no other floodplain tree that’s shade-tolerant, flood-tolerant, and long-lived," Goodwin notes. The project is an attempt to reconstruct this natural defense system, one sapling at a time.
Scientific Perspectives: Resistance vs. Tolerance
The distinction between "resistance" and "tolerance" is central to the current research. While early breeding efforts sought trees that could entirely repel the disease, current researchers are looking for trees that can coexist with it.
Leila Wilson, a research ecologist with the U.S. Forest Service, admits the process is harrowing. "I feel like we should warn them and apologize to them because we’re torturing them," she says. "I don’t like that part. But they’re serving the greater good."
The "greater good" relies on the fact that, after decades of carnage, the few trees that remain standing in the wild are likely there because they possess a genuine biological advantage, not just luck. By collecting cuttings from these veterans—such as the "Rainbow Beach" elm in Massachusetts—scientists are working with a more promising genetic pool than their predecessors.
"This is the playoffs," says Christian Marks, an ecologist formerly with TNC who was instrumental in the project’s design. "What you’ve been preparing for."
Implications: A Future for the American Elm
As the research progresses, the team is documenting every development in a custom app. Trees are marked with orange paint, and their progress is tracked from initial inoculation to either collapse or resilience. Early data from the Benson site is cautiously optimistic; nearly 800 trees have not yet shown symptoms of infection, a promising sign that their genetic makeup may hold the key to long-term survival.
However, experts emphasize that we cannot repeat the mistakes of the past. The widespread planting of American elms in the early 20th century created a monoculture that made the species an easy target for a single pathogen. Modern urban planners are advocating for a "diversified portfolio" approach to city forestry, ensuring that elms are part of a broader, more resilient ecosystem rather than the sole occupant of the canopy.
A Moral Imperative
Beyond the data points and the logistics of seed orchards, there is a profound philosophical component to this work. "There’s kind of a moral injury of extinction," Goodwin reflects. "This is a way to try to repair that."
Whether or not the Benson test site produces a miracle, the effort to save the American elm serves as a testament to the tenacity of human stewardship. On the edge of the test plot stands the "Benson tree," a large, unruly, and majestic elm that has outlived its peers. It is a silent witness to the researchers who labor in its shadow, attempting to ensure that its kin will not be the last of their kind to grace the American landscape.
For now, the work continues: the drills whir, the pipettes dispense, and the scientists watch the orange-marked trees, waiting to see which ones will stand when the dust—and the fungus—finally settles.
