In a quiet 28-acre grove in southern Vermont, a high-stakes experiment in ecological survival is underway. Gus Goodwin, the director of science and technology advancement at The Nature Conservancy in Vermont, kneels before a young American elm. Dressed in utilitarian field gear, he carries a tool that seems antithetical to his mission: a drill.
With a measured, precise motion, he bores an inch-deep hole into the trunk. He then retrieves a blue pipette and administers a dose of approximately 100,000 spores of the fungus responsible for Dutch elm disease (DED). This is not an act of vandalism, but a calculated, clinical effort to identify the few trees that possess a natural, genetic tolerance to the pathogen that has decimated one of North America’s most culturally significant species.
Across the sprawling site, nearly 5,300 elms—the progeny of survivors found across New England—are undergoing this same "vaccination." It is a brutal process, one that requires the loss of the many to identify the exceptional few. If successful, this project could produce the largest, most genetically diverse population of disease-tolerant American elms in over a century, offering a lifeline to a tree that once defined the American landscape.
A Historical Titan in Decline
The American elm (Ulmus americana) is more than just a tree; it is a biological and historical pillar. Known for its cathedral-like canopy, which can soar 100 feet into the air, the species was once the undisputed king of the North American floodplain. Its vase-like architecture and rapid growth made it a favorite for city planners and homeowners alike.
In the 19th and early 20th centuries, the elm was a symbol of American identity. It graced the village greens of New England, provided shade for Revolutionary War councils, and lined the "Main Streets" of countless small towns. As Henry David Thoreau famously noted in his journals, the elm was distinguished by its beauty, visible from great distances under both sunlight and moonlight.
However, the 20th century brought a catastrophic turning point. Dutch elm disease, a fungal pathogen (Ophiostoma ulmi and the more aggressive Ophiostoma novo-ulmi) likely imported via timber shipments, began its march across the continent. Carried by native elm bark beetles, the fungus triggers an aggressive immune response in the tree, causing it to clog its own xylem—the vessels that transport water and nutrients—with balloon-like structures called tyloses. In effect, the tree starves to death, often in as little as a single year.
The Chronology of an Ecological Collapse
The devastation wrought by DED represents one of the most significant events in the history of urban forestry.
- 1922: Dutch scientists formally describe the fungus, which had been observed in northern Europe as early as 1910.
- The 1930s: As the disease reached North America, the federal government, under President Franklin Delano Roosevelt, allocated $2.5 million for removal efforts. Unfortunately, the strategy of "culling" proved disastrous, as the fungus often spread through interconnected root systems—a phenomenon scientists did not yet fully grasp.
- The 1940s: World War II diverted critical resources away from forest management, allowing the more lethal Ophiostoma novo-ulmi strain to take hold.
- The 1970s: The epidemic reached a fever pitch. Minneapolis, for example, was forced to remove over 20,000 elms annually. By the end of the century, roughly 95% of the American elm population had been wiped out.
The Science of Survival: Breeding for Tolerance
Modern efforts to revive the elm have shifted from reactive culling to proactive, genetic-based restoration. Unlike the American chestnut, which has benefited from gene-editing technology, the American elm’s resistance is polygenic—meaning no single "magic bullet" gene can be modified to grant immunity. Instead, researchers are returning to the methods of 19th-century botanists like Gregor Mendel: patient, generational crossbreeding.
The challenge is immense. By some estimates, only one in 100,000 elms is truly tolerant to DED. Early attempts, such as those conducted at Cornell University between 1937 and 1965, were largely unsuccessful, resulting in high mortality rates and little long-term success.
However, the current generation of researchers, including Christian Marks and Jim Slavicek of the U.S. Forest Service, are building on the lessons of the past. By collecting cuttings from "survivor trees"—mature, healthy specimens found in the wake of the epidemic—they have identified candidates with potential genetic defenses. The Benson, Vermont plot is the testing ground for this new lineage. The goal is to identify trees that can survive repeated exposure to the fungus, not just once, but throughout a life cycle that should span over a century.
Official Perspectives and Expert Analysis
The project has garnered significant attention from the scientific community, though experts remain cautious. Stephanie Adams, a tree pathologist at Texas A&M University, notes that while the "junkyard dog" resilience of the elm makes it a prime candidate for restoration, the lessons of the past must be heeded.
"One lesson we learned… was not to plant a monoculture of trees," says arborist Doug Still, host of the This Old Tree podcast. This sentiment is echoed by Ryan Murphy of the University of Minnesota, who emphasizes that current urban forestry efforts focus on diversification as a safeguard against future biological threats.
Despite the warnings, the morale among the researchers in Vermont remains high. During a recent check of the Benson test site, researchers Chris Hansen and John Butnor observed a diverse range of responses. While some saplings were already showing signs of decline, others appeared remarkably healthy.
"You hear us throw around the words resistance and tolerance, and I think most of the time we should actually be saying tolerance," Hansen remarked. The distinction is vital: the project aims to create trees that can endure the presence of the pathogen, living alongside it rather than expecting total eradication.
Broader Implications: Floodplains and Climate Change
The urgency of this project is amplified by the climate crisis. American elms are uniquely suited for floodplains; they are shade-tolerant, flood-tolerant, and exceptionally long-lived. As climate change increases the frequency and intensity of "100-year" weather events, the restoration of these forests is not merely an aesthetic choice, but an economic and safety imperative.
One study suggests that restoring healthy floodplains in New England could save up to $1 billion in property damage over the next century by providing natural, high-capacity flood mitigation. Furthermore, the elm supports a specialized ecosystem, including species like the double-toothed prominent moth, whose larvae have evolved to camouflage perfectly with the elm’s unique leaf structure. Replacing the elm with a non-native substitute would, in effect, "pull the rug out" from beneath these specialized creatures.
Conclusion: A Moral Mandate
Is the effort worth the cost? To the scientists in the field, the question is almost irrelevant. For them, the work is defined by what Gus Goodwin calls "the moral injury of extinction."
The project is a long game. The researchers will monitor the Benson grove for another two years to identify the most robust parents, after which it will take another 10 to 15 years for the new generation of "super trees" to bear seed.
On the edge of the Benson test site stands a mature, "unruly" elm that has somehow defied the odds. It is a testament to the tree’s tenacity. As the researchers continue their work, this "Benson tree" stands as a silent witness to the endeavor—a living bridge between the lost forests of the past and a potential, greener future. Whether the next generation of elms can reclaim their place in the American landscape remains to be seen, but the commitment to the cause suggests that the elm’s story is far from over.
