Could one of our most important trees disappear with barely a whimper?

A mysterious disease aided by an apathetic bureaucracy could doom the American beech

I hate to be a bearer of bad news, but if you live in the eastern United States, as I do, a big change could be coming to the woods near you. It’s a change that even if you’re only a casual visitor to the forest, you will probably notice. A new, mysterious and potentially deadly disease is going after one of our most common and important trees.

This is a major unfolding nature and biodiversity story, yet I’m guessing you haven’t heard of it. I’m hoping to bring it to wider attention. So if, after reading this post, you feel similarly that this is something more people should know about, I hope you’ll consider sharing it widely.

But first, let’s meet Fagus grandifolia, the American beech.

Lichen and moss festoon the roots of an old beech tree in Washington, DC’s Rock Creek Park (all photos by me unless otherwise noted)

In many ways, recent decades have actually been good times for beech trees. Many of our second-growth forests are reaching middle age, when speedy pioneer trees like tulip poplar give way to slower-growing, shade-loving beeches. Deer that chomp on seedlings of other species often avoid beech. Regular fires that once suppressed beeches in favor of oaks, hickories and chestnuts have themselves been suppressed.

Beech is thriving here in the Mid-Atlantic where I live. It's now the most common tree in Washington, DC; the second most common in neighboring Fairfax County, Virginia. In Maryland it's gaining ground faster than any other tree. And that's good news for those of us who spend time outdoors, because the beech is a beautiful, graceful tree — and one of the easiest to recognize, with distinctive, smooth, all-too-easily carved grey bark that has recorded innumerable youthful loves. In winter beech holds fast to its tawny brown leaves, offering color and variety in otherwise dull woods¹.

Young wintertime beeches in Rock Creek Park

This beech tree is doing fine 59 years after being carved. Any bets on whether Pat and Bob’s romance is too?

Some beech trees have reached grand proportions, standing as tall as forest giants like oak. But the good times might be coming to an end thanks to a strange new disease that's spreading with alarming rapidity — and that some experts fear could wipe out American beech, one of the most important trees in the eastern United States.

The oddly striped and crinkled leaves that are a hallmark of this disease first appeared in 2012 near Cleveland. They popped up in western New York in 2015, New York City and its suburbs in 2019. In 2020, beech leaf disease reached the Atlantic coast² and just last month it was confirmed in the northern Virginia suburbs, where I snapped a few photos of it near dusk last fall. Meanwhile, trees infected for several years have shrunk to shriveled, ghostly versions of their former selves; some have died.

Diseased beech leaves in Prince William Forest Park, VA

It’s always a struggle to know how alarmed to be when something like this pops up. Sometimes trees find ways to defend themselves against new pests, and we don’t necessarily need to intervene. But what I’m hearing from experts suggests that it’s time to be pretty alarmed. Some are starting to openly call beech leaf disease "the next chestnut blight" — a frightening new iteration on the devastating plague that wiped out some 4 billion trees in the early 1900s.

Similar to the once-mighty American chestnut, American beech grows throughout the eastern half of the country. They're "almost omnipresent" in the forests of the Northeast, says Bob Marra, a forest pathologist with the state of Connecticut. Kelsey McLaughlin, a New York state pathologist, told me that a quarter of all calls and emails her team got from the public last year were about distressed or dying beeches, which abound in the woods of counties like Westchester. "It's our main public concern," she said.

Ecologically speaking, losing a major tree is about the worst thing that could happen to a forest. It’s not like losing, say, a small rare plant, or even a charismatic animal like a bird. Trees are the foundation stones upon which everything else rests. Beech nuts feed bears, deer, porcupines, turkeys and many other animals, especially in northern states where few oaks or other nut-bearing trees grow. And like all our native trees, beech has, over evolutionary time, accumulated its own bespoke ecosystem of fungi, insects and other life forms. If beech were to die out, the ripple effects on wildlife and carbon storage would be profound and long lasting.

As much as we might mourn these losses, we are still humans, and the species we care most about is our own. And while beech leaf disease is not going to have covid-level societal impacts, it will affect us, too. Even if you’re someone for whom one tree looks more or less like any other, a decline in beech health will be starkly noticeable. Beech saplings make up more than a third of the understory in forested parks such as DC's Rock Creek Park and Virginia's Prince William Forest Park (where the region's first detection occurred). These lush urban and suburban forests, which so many of us rely on for refuge and recreation, could soon be full of sickly, shriveled trees.

Beechy understory of Rock Creek Park. Photo by Katja Schulz from Wikimedia Commons.

Beech is a huge part of what makes our woods feel woodsy, because its leaves and branches so often live at the level at which we experience the forest. And in places where it’s abundant, there’s no other tree that can quickly fill beech’s niche. It’s too early to say how severe this disease will be, but from what we know already, it seems very probable that our forests could be severely depleted for years or even decades to come.

Such devastation would not just be ugly and sad; it could have tangible impacts on our collective wellbeing. A growing body of research links urban forest declines to increased risk of health conditions such as depression and heart disease. It’s become almost a cliché to point out that our health and the health of our environment are related, but beech leaf disease could prove the point in visceral terms.

So it’s frustrating to have to report that a decade into this fast-spreading tree epidemic, scientists are still struggling to figure out what exactly beech leaf disease is, much less how to stop it. As I reported in 2018 and 2019, scientists have discovered a tiny worm called a nematode feasting on the leaves of diseased trees. (Leaf-feeding nematodes causing a major tree disease is super weird, by the way!) While it’s believed to have been introduced from Asia, similar to many of our other forest pests, that hasn’t been proven.

Microscope image of the nematode Litylenchus crenatae ssp. mccannii, thought to cause beech leaf disease. Photo by Gary Bauchan, Joe Mowery and Lynn Carta, USDA-ARS

One thing that's certain is that the nematode is capable of long jumps. In 2021 it showed up in Prince William County, Virginia, 100 miles from the closest known infested site. The nematode could be hitching a ride with birds, although nobody has proven it. Researchers at Ohio State University are also looking into whether bacteria or fungi could be involved in the disease.

These scientific question marks are hindering progress against the disease, but they’re not the only factor. It took several years after the initial detection for the federal Animal and Plant Health Inspection Service, or APHIS, to get involved. When APHIS experts finally took a look, they deemed the disease already so widespread that they declined to consider a quarantine on beech trees — one of the government’s most powerful tools for slowing the spread of plant diseases. Ten years in, APHIS still sees beech leaf disease “as a research question more than a regulatory question,” Stephen Lavallee, the agency’s national policy manager, told me.

There may be a reason for the bureaucratic inertia. Beech is of little value as a timber tree; indeed, many forest professionals hate it. And because our under-resourced plant protection and research bureaucracy prioritizes species of commercial value rather than, say, ecological or public value, few resources have been devoted to understanding beech leaf disease or protecting beeches.

Only a handful of scientists are even studying the disease, often with funding they've had to scrape together, rather than dedicated grants. APHIS has funded exactly one beech leaf disease-focused research grant, to map where beeches are at risk. Many of those areas already have the disease. (In fairness, APHIS has never received anywhere close to the funding it would need to adequately protect all our threatened trees.)

It's striking to compare the anemic response to beech leaf disease to the all-hands-on-deck mobilization against another tree pest: spotted lanternfly, a charismatic bright red insect that showed up around the same time. The lanternfly goes after commercially valuable grape vines and orchard trees. The public has been marshalled to murder lanternflies — and responded with impressive, if perhaps unsettling, enthusiasm. Numerous scientists are studying the bug, and states like New Jersey have invested in billboards admonishing us to "stop. scrape. squash." The media have run story after story on the insect; it even made an appearance on Saturday Night Live.

Meanwhile, hardly anyone has even heard of beech leaf disease, despite the fact that it attacks a more ecologically important tree than any feasted on by the lanternfly. (Indeed, the lanternfly's preferred host is the tree-of-heaven, which most ecologists consider a damaging invasive we would be better off without.)

Time and again we're told we're in an extinction or biodiversity crisis. And yet time and again, when a new biodiversity threat appears, we hardly muster a response. Now we're poised to lose yet another major component of what was once the world's greatest temperate forest. It’s not clear how many more times we can repeat this movie before there are no more trees left to lose.

Old beech in Maryland’s Patuxent Wildlife Refuge, another extremely beechy forest

---

If you’ve read this far, thank you. I started this newsletter to publish pieces like this — pieces you won’t read anywhere else. In this case, that’s literally true — several major outlets declined my pitches to report for them on beech leaf disease.

To me, this is a prime example of a major nature and biodiversity story that just doesn’t fit into the boxes that the media find important, and that has never reached public attention, despite the profound impact it could have. And because it’s gotten so little attention, there has been little pressure on governments or anyone else to respond. That inattention could come back to haunt us.

If you find this kind of reporting valuable, please consider supporting The Nature Beat by becoming a paid subscriber and/or forwarding this piece to others.

1. This mysterious yet beautiful trait is known as marcescence. There’s an interesting discussion here of why some trees seem to be neither fully deciduous nor fully evergreen.

2. Credit is due to Faith Campbell of the Center for Invasive Species Prevention, which published this map, for being one of the few people trying to draw attention to beech leaf disease.