One of the most resilient trees on Earth is dying in droves

On a brisk December day, David Stahle stands atop a ladder leaning against a bald cypress tree as wide as he is tall. Like a woodsy Doctor Who dropped into this southern swamp with a sonic screwdriver, Stahle begins slowly boring through time.

The first inch takes him back to before the First World War, the second to the birth of the United States. Within five inches, Stahle, a dendrochronologist at the University of Arkansas, has reached Columbus’s voyage to the New World. By the time he’s finished extracting the pencil-thin core, Stahle has enough rings to estimate that the gnarled cypress sprang from its sodden bed as the first Crusaders were marching toward Jerusalem about a thousand years ago. But it’s the half-inch sliver close to the bark, from around 1900 to 1935, that Stahle points out.

By the end of that period, roughly 90 percent of the ancient bald cypresses in the U.S. had been cut, Stahle says. “There’s less than a tenth of one percent of the original bottomland cypress swamp left” in the country. “That’s why this place is something special.”

“This place” is an overlooked patch along North Carolina’s Black River that contains the oldest known trees east of the Rockies. In fact, the bald cypress is the fifth oldest known sexually reproducing tree species on the planet. The tree Stahle has just cored is barely middle-age. One cypress he discovered here in 2017 dates to at least 605 B.C., not long after Homer regaled the Greeks with the adventures of Odysseus. That makes it over 2,600 years old, and Stahle has found several others of similar vintage nearby. The data from their cores and from other bald cypresses in the Southeast form one of the longest and most accurate records of soil moisture in science. Decades-long droughts, as well as wet periods known as pluvials, are clearly written in their rings down to the exact year. These include a drought that may have doomed England’s first foothold in the New World, Sir Walter Raleigh’s famous Lost Colony, in 1587, and a second one in the 16th century that was even worse.

“The 20th century is not representative of the extremes those trees have endured,” says Stahle, who has cored ancient trees all over the world. A 16th-century megadrought “extended from Mexico to Canada, from the Atlantic to the Pacific, and lasted almost 40 years. We haven’t seen anything like that in the modern era.”

While these ancient trees provide a window on our climate past, their siblings closer to the coast are teaching us an equally important lesson about our climate future. Even though bald cypresses are among the most resilient trees on Earth—able to withstand some of the worst conditions nature can muster—cypress forests are now dying in droves along the coastline from Delaware to Texas, leaving bone white skeletons in their wake.

These ghost forests are perhaps the clearest signal we have of the inexorable rising tide that is pushing salt water deep into once freshwater ecosystems. Although bald cypresses are more salt tolerant than the ashes, oaks, and other species that share their forested wetland home, they can’t survive long with more than two parts per thousand (ppt) salt in their water. The Atlantic Ocean can exceed 35 ppt, and the level of the ocean is rising faster along the eastern seaboard than almost anywhere else on the planet. Sea level in nearby Wilmington, North Carolina’s largest port, has risen about 12 inches since 1950 and is projected to rise at least another foot by 2050. The Black River trees aren’t currently threatened by salt water; the river remains a quintessential blackwater stream. But farther downstream in the Lower Cape Fear watershed, at least 800 acres of forested wetland have turned into salt marsh since the 1950s as the water has become more brackish, according to recent research from the University of North Carolina at Wilmington. Once annual average salinity hits the 2 ppt mark, the conversion from forest to marsh becomes inevitable.

Cape Fear’s ghost forests, which can be seen from area bridges, are a microcosm of a much larger trend. A recent study by researchers at the University of Virginia and Duke University using satellite imagery found that the Gulf Coast and Atlantic coastal plain lost more than 5,000 square miles, or 8 percent, of forested coastal wetlands between 1996 and 2016. That’s a Connecticut-size swath of forest that is now mostly salt marsh and scrub. And almost 270 square miles continue to disappear each year—more than triple the loss rate of global mangroves, long considered one of the most threatened ecosystems on Earth. The researchers concluded that at that pace, barring widespread protection or restoration efforts, we could lose all our coastal forested wetlands before the century’s end.

Bald cypress swamps were North America’s Amazon 120 years ago, covering an estimated 40 million acres of the serpentine forested wetlands of the South. They were home to magnificent ivory-billed woodpeckers, delicate Bachman’s warblers, and swarms of Carolina parakeets, not to mention a plethora of aquatic species. But protecting swamps has long been a hard sell. In fact, they are perhaps the only ecosystem that has been specifically targeted for destruction by the federal government.

The Swamp Land Act of 1850, and another like it, gave unclaimed federal wetlands to several southern states, requiring that the proceeds from land sales be used to drain them. None other than the great orator Daniel Webster summed up the general sentiment in 1851: “[N]othing beautiful or useful grows in it; the traveler through it breathes miasma, and treads among all things unwholesome and loathsome.”

Unlike their close cousins the redwoods and giant sequoias, cypresses had no organization like the Save the Redwoods League to lobby for their protection. No Ansel Adams–worthy vistas to show the nation what was at stake. As soon as loggers developed cable logging, steam-powered skidders, and other technologies that enabled them to reach deep into the swamps, they set upon them like beavers, turning acres of old-growth cypresses into siding, shingles, even banana crates, until only the most isolated pockets of the ancient trees remained. The Carolina parakeets, ivory bills, and Bachman’s warblers eventually vanished as well.

On a cool, clear autumn day with no miasma in sight, National Geographic Explorer Mac Stone, Stahle, and local guide Charles Robbins launch their kayaks into the Black River’s labyrinth of channels, flowing with water the color of fine bourbon. Their goal is to visit the 2,000-year-old trees Stahle discovered in 2017, and to find and core three more denizens that Stone had spotted during an aerial survey of the area, known locally as the Three Sisters Swamp. The stillness of the swamp is palpable, broken only by paddle drips and the heart-stopping flush of brightly colored wood ducks. Without Robbins’s local knowledge, getting lost would be almost instantaneous. Robbins has lived in Wilmington since the 1980s and has seen the ghost forests creeping up the Cape Fear River, hammered by a trifecta of sea-level rise, dredging of the ship channel, and frequent hurricanes.

“They all got beat to hell during Bertha and Fran,” Robbins says, referring to the two hurricanes that scored direct hits on the Cape Fear region in 1996, causing major flooding and billions of dollars in damages. “Many tops were broken off, and they were coated with salt spray. They just started to decline.” The water around the Three Sisters is not salty, he says, but it gets hit from heavy nutrient loads upstream in Sampson and Duplin Counties, which have the highest density of hogs in the nation and untold numbers of chicken and turkey farms. Nearly all the waste from millions of hogs, chickens, and turkeys is spread on fields.

Mature cypress forests are incredibly good at cleaning up water—some have even been used to treat municipal sewage in Louisiana. But such high levels of nutrients invite alligator weed, an exotic species, to settle in, and it can outcompete young cypress seedlings.

En route to Stone’s trees, the boats are eventually blocked by a phalanx of cypress knees, some more than 10 feet tall, so the group abandons the kayaks and sloshes through the boot-sucking muck to the rough GPS location on Stone’s map. One key to the oldest trees’ survival, Stahle believes, is that they have a certain “gnarl factor” that makes them worthless as lumber. The trees they find are no exception. They sport massively swollen and fluted bases festooned with burls the size of kitchen tables. The first tree’s top is split and ragged, torn off by some punishing storm and then regrown willy-nilly. The second has a trunk that divides into two 50 feet up, then spirals together like giant flamingos. The last has a hollow that once housed a black bear big enough to scrape its mark seven feet off the ground. (Eastern North Carolina has some of the largest black bears in the world.) Though he can’t core the hollow tree, Stahle estimates it is likely as old as the other two, which have lived at least a thousand years.

“That’s the thing about old trees,” says Julie Moore, a retired biologist from the U.S. Fish and Wildlife Service, who pointed Stahle to the Black River in the early 1980s when she worked for the North Carolina Natural Heritage Program. “They wouldn’t have lived this long if they couldn’t take it. Species that have been with us a long time have to adapt.”

Many of those adaptations could prove invaluable to humans in a hotter, drier, and stormier world. One study found that even young cypress trees can withstand months of flooding more than 30 feet deep, while their trunks, their knees, and the swampy soils around their roots absorb stormwater and carbon like a sponge. Stahle has shown they can survive decades-long droughts, and others have determined that cypresses can contribute to groundwater recharge and even filter some contaminants. Their high salt tolerance often makes them the last of the ghost forest trees to go. But it’s an uncanny ability to survive the most powerful storms on the planet that makes them truly unique.

William Conner interviewed for a research job at Clemson University’s Belle W. Baruch Institute of Coastal Ecology and Forest Science in Georgetown, South Carolina, two weeks after Hurricane Hugo blasted the state in 1989. The Category 4 storm came ashore with winds of nearly 140 miles an hour, damaging some 4.4 million acres of forest and destroying 6.7 billion board feet of sawtimber—enough to build about 660,000 homes. That would have housed almost the entire state of West Virginia at the time.

“When I drove through Francis Marion National Forest, all the pines were flattened to the ground,” says Conner, now professor emeritus at the institute. “All the cypress along the streams were still standing. They are incredibly wind-fast, with their buttresses and knees and intertwined root systems. I’ve only seen two trees blown over in my career, and both were isolated by themselves.”

That makes them particularly good for restoration projects in places like Louisiana, which once may have had the greatest cypress forests on the continent. Hurricane Katrina was able to flood 80 percent of greater New Orleans in no small part because the city was built on old cypress swamps that were logged and drained, and it eventually sank many feet below sea level. But with several freshwater diversions now in place and the closing of the Mississippi River Gulf Outlet shipping channel, which was a direct conduit for salt water from the Gulf of Mexico into the Lake Pontchartrain Basin, conservation groups have been steadily planting cypresses to restore the region’s lost hurricane buffers, among other benefits.

The Pontchartrain Conservancy has planted about 92,000 trees since 2010. “We’ve been getting anywhere from 65 to 98 percent survival rate depending on the site,” says Michael Hopkins, who runs the conservancy’s planting program. “Some of the trees are now 30 to 40 feet tall. When they become mature adults, they can be there for centuries, as long as there is enough fresh water.”

As the shadows lengthen on the Black River, Stahle, Robbins, and Stone paddle back toward the Three Sisters grove to set up camp on a sandbar where a copse of ancient cypresses blots out the stars. After Stahle found the first Roman-era trees in the mid-’80s, the Nature Conservancy began buying land and conservation easements around the grove. It now owns some 17,000 acres along the Black, including the area around the oldest trees. Stahle doesn’t think that’s enough. A proposal to create a Black River state park fizzled in 2017 after some local residents expressed concern about the effects an influx of visitors might have on the old trees—and the quiet, rural community—even though a statewide survey conducted that year found strong support for state protection.

“They are at two meters of elevation, near the coast, so they are threatened [by sea-level rise],” Stahle says. “At that level we’ll be losing cities, and we can’t allow that to happen. But even the small remnant old-growth forests can be the core area of a broader plan of ecosystem restoration. I’d like to see it protected as a national preserve or monument.” He cites the creation of South Carolina’s Congaree National Park as an example.

One of Earth’s oldest trees stands a hundred feet away, as it has throughout the ravages of the past 2,600 years. Its busted top is sprinkled with resurrection ferns, so named, Stahle says, because they can lose nearly all the water in their tissues during drought, turn gray as death, then spring back to life, good as new, at the first rain. They seem a fitting accessory for this ancient member of a species long known as “the wood everlasting,” which with care and conservation could help us adapt to a warmer, stormier world.