The Paradox of Pestilence
Ecological Hope in a Landscape of Tree Death
Editors’ Note: Wildlands, Woodlands, Farmlands & Communities envisions a healthy New England landscape where long-term conservation supports biodiversity and healthy human communities, even in the face of climate change, habitat loss, and invasive pests and pathogens. Colby Galliher focuses on a few especially worrisome forest pests and muses about how our attitudes toward them might lead us to hope, rather than despair. What can we learn from the drastic response to chestnut blight in the early twentieth century? Can we do things differently? Are there lingering survivors of beech, ash, hemlock (see Issue #4), and elm that can lead us back to healthy populations of these species? Read on. Or, if you prefer, listen on.
The American beech trees of southern Connecticut’s Chatfield Hollow State Park are ailing. Over the summer, leaves which should have shimmered svelte and silver-green hung withered and leathery. Some trees, with smooth, stately trunks sporting level branches like spokes, stood naked; now, in winter, most lack even the translucent, faded leaves that typically persist through the cold months. This forest is infected with beech leaf disease (BLD), a malady caused by an invasive nematode from East Asia. Early assessments of BLD’s lethality suggest that affected trees, from wizened elders to humble saplings, will die in a matter of years. In these woods, at least, the writer finds no beech spared of symptoms.
Beech leaf disease in a Connecticut forest. Photo © Tyler Russell, Connecticut Public
Healthy American beech leaves in spring and in fall. Photos © Liz Thompson
If BLD proves as disastrous as currently observed in areas across the species’ range, the American beech may join ash, hemlock, American elm, and American chestnut in a club of toppled giants. These are tree species once or still common in New England forests whose populations have precipitously declined or, based on the latest predictions, are likely to do so soon, in a mere geological second, despite attempts to save them with biological and chemical interventions. They are the poster children of a human-induced violence that is less overtly brutal, but more intractable, than the rampant deforestation of previous centuries: Pests travel across oceans in shipping containers of inexpensive goods, their infestation of North American forests engendering wholesale disruptions to even those few old-growth ecosystems we have managed to spare from harvest. This slower-moving carnage is a reminder that even as we have learned (sometimes) to tread more gently on forests in our corner of the planet, our global appetites breed new vehicles for unmaking ecosystems.
“Instead of trying to extract every crumbling dollar from these ill-fated trees, we might embrace the paradox of ecological opportunity amid the mayhem we have loosed on our woods.”
But what if, in these calamities we have unintentionally wrought upon our woods, there were something ecologically positive to be gained? If the lion’s share of hemlock, beech, and ash succumb as predicted, billions of their corpses will litter a regional landscape deprived for centuries of the snags and coarse woody debris so critical to healthy forest ecosystems. By simply letting these casualties be, rather than preemptively clearing or logging them for salvage, we might allow genetically resistant individuals to persist and reduce the deficit of dead wood on the land. It is a paradoxical opportunity, one that confounds deeply held beliefs about our role as landscape stewards in the Anthropocene—and that tests our capacity to learn from past mistakes.
A Cautionary Tale
We have inadvertently unleashed mass tree death before. Chestnut blight, an East Asian fungus introduced to North America via imported Japanese chestnut trees, swept across the eastern United States in the first half of the twentieth century and killed between 3 and 4 billion American chestnuts. As the blight spread, a concerted effort arose to salvage the remaining economic value of the moribund species by cutting not only dead and dying but also living trees.
This approach likely exacerbated the blight’s ecological impact. By indiscriminately removing living trees before the death march reached them, we may have snuffed out mature individuals that harbored some amount of genetic resistance and could have formed the basis of an organic, blight-resistant repopulation. This furious effort also deprived forest ecosystems of a welcome infusion of dead wood. Though the chestnut’s ability to sprout prolifically from stumps has held off its total extinction, the blight knocks back these upstarts before they can mature, preventing widespread establishment of long-lived, mast-producing adults.
In northwestern Vermont, a few healthy American chestnut trees survive and produce fruit year after year. These individuals were likely spared because of their distance from the nearest population of blighted trees. Could they offer hope for the future? Photos © Liz Thompson
Our handling of the chestnut blight, then, offers a cautionary tale as we refine strategies for the ongoing decline of beech by BLD, ash by the emerald ash borer, and hemlock by the hemlock woolly adelgid (HWA). It is still too early to speak categorically about these species’ futures, but reports from infested areas suggest that many, if not most, individuals will perish over the coming decades. Instead of trying to extract every crumbling dollar from these ill-fated trees, we might embrace the paradox of ecological opportunity amid the mayhem we have loosed on our woods.
Heeding—or Not—the Lessons of the Past
At first glance, it appears that the lessons of the chestnut blight may go unheeded. Today, many foresters, loggers, and landowners are preemptively harvesting beech, hemlock, and ash, or are encouraging others to do so. This salvage-logging approach robs forests of their standing dead trees and fallen logs, impacts soils, and frequently removes other species. These blows compound the damage of centuries of human land-use patterns and forestry practices that have stripped biological legacies from the landscape to the detriment of the forest carbon cycle and countless mammals, birds, reptiles, and amphibians.
There is a better alternative to this old, damaging playbook—one that embraces the ecological possibility of the pestilential wave blanketing our forests. Many foresters and landowners already manage their holdings with ecosystem health and climate resilience in mind, fortifying their woods against a tumultuous future of invasive species, pathogens, and natural disasters. Rather than interfere with these management goals, the natural landscape-level changes brought on by the irreversible decline of hemlock, beech, and ash, as with chestnut, would likely serve them by helping to chip away at long-standing deficits of dead wood and insufficient structural complexity. Foresters and landowners could achieve their overarching management aims and save resources by abandoning attempts to arrest an unavoidable process of death and transformation.
“What if, in these calamities we have unintentionally wrought upon our woods, there were something ecologically positive to be gained?”
Decades, if not centuries, might pass before evolution allows these species to flourish again in our woods, but leaving these trees on the landscape may be their and the forests’ best hope—and would be a repudiation of our misguided approach to the chestnut blight. In the meantime, resources could be better funneled into proactive government and private-sector strategies to preempt the next outbreak by more tightly regulating the international and interstate flow of wood products.
There are promising signs, however piecemeal, that some government and industry stakeholders are revamping their approach to insect and pathogen damage along these lines. In Massachusetts, the Healey administration is, as of this writing, considering forest management guidance that evinces a greater awareness of natural disturbance and the resulting dead wood as vital components of healthier and more resilient forests. Maine’s Department of Agriculture, Conservation & Forestry recommends that landowners with substantial beech stands refrain from pre- or post-infection harvesting in order to promote genetic resistance and provide habitat for wildlife. A similar approach is recommended for ash by the Vermont Land Trust.
Still others are incorporating this mentality into efforts to help these species along toward pest resistance without the ecological dragnet of salvage logging. The Nature Conservancy and the U.S. Forest Service have teamed up on Trees in Peril, an innovative new project toward this end. The project aims to develop pest-resistant breeds of elm, beech, ash, and hemlock by identifying surviving individuals in the wild that might support future repopulation. A subset of Trees in Peril, the Lingering Hemlock Project, zeroes in on the establishment and eventual propagation of native, adelgid-resistant hemlocks. (Read Hemlocks Saving Hemlocks in Issue #4.)
On the left, a healthy hemlock branch. On the right, one afflicted by the hemlock woolly adelgid, in the hand of David Orwig, researcher at Harvard Forest. Left Photo © Liz Thompson, Right Photo © Lynda Mapes
This guidance could be complemented by targeted government incentives for landowners to avoid harvesting beech, ash, and hemlock on their property, as opposed to incentives to clear them. Better still would be to use these disturbances and their aftermath to advocate for the rewilding conservation ethos currently applied to and playing out on Wildlands across New England, where the ebb and flow of nature proceeds, as it has for millennia, without human intercession.
Conclusion: The Human Dimension
Behind this proposed recalibration is another, symbolic logic. We have convened commissions, built museums, and erected striking monuments to atrocities we humans have inflicted on each other. These somber memorials are designed to remind us of the horrors of our worst impulses and to serve as a hedge against their recurrence.
“Decades, if not centuries, might pass before evolution allows these species to flourish again in our woods, but leaving these trees on the landscape may be their and the forests’ best hope.”
To leave forests of dead ash; groves of petrified hemlock; hulking shells of once-regal beech; beetle-carved logs of American elm: Could these statuaries of the dead prompt us to confront what we, through our recklessness, have inflicted upon the forests that sustain us?
To acknowledge the ecological disruption of which we are capable?
To internalize that seemingly harmless choices in our modern world have the potential to undermine ecosystems?
These stunning traces of the elm bark beetle, which is a vector for Dutch elm disease, are a reminder, on the forest floor, of the disease’s devastating effects. Photo © Liz Thompson
In our response to the upheaval we have caused is the paradoxical potential to rectify our past errors; to usher in a future where we do not simply slash and grind down the grim results of our missteps, but reckon with them, and consider ways in which they may push us toward a healthier, more mindful relationship with our forests and the nonhuman world.
Colby Galliher writes about conservation, wildlife, and environmental policy. He was previously a researcher and analyst at a public policy think tank in Washington, D.C. In that role and others, he has written a book chapter, scholarly reports, and articles for local, regional, and national publications. His short fiction has also been published in a variety of literary journals. He is the Editorial Communications Specialist at Northeast Wilderness Trust.