The oldest tree in eastern US survived millennia – but rising seas could kill it

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The oldest tree in eastern US survived millennia – but rising seas could kill it

Cypress trees have towered over the Three Sisters swamp in North Carolina's Black River for more than 2,600 years.

A 2,624-year-old bald cypress could teach us how to fight climate change – if it doesn’t get destroyed first

Ayurella Horn-Muller

Last modified on Sun 1 Aug 2021 15.23 EDT

A wizened eastern bald cypress dwells in an expanse of North Carolina’s wetlands.

It lives among a cluster of eastern bald cypress trees in the state’s Black River, some with origins dating back a millennium. But this singular tree has witnessed more than its comrades; a 2019 study found it’s been alive since at least 605BCE. It’s the oldest-known living tree in eastern North America and the fifth-oldest living non-clonal tree species in the world.

If these ancient trees could talk, they might wail a warning – a message about the coalescing threats to their continued survival. What we can learn from a 2,624-year-old bald cypress may help piece together how humanity can best mitigate and adapt to the unprecedented impacts of the climate crisis.

“They have personality,” said Julie Moore, a retired botanist and former coordinator at the US Fish and Wildlife service. “I’ve mapped wetlands for years, so every big swamp in the United States in the south, I’ve seen. But when I see these trees, I know they’re different.”

Back in 1985, Moore introduced David Stahle to the Black River’s bald cypress stand. A dendrochronologist, Stahle began using tree ring mapping and radiocarbon dating on the trees, leading to his discovery of “Methuselah”, a bald cypress dating back to 364AD.

It would take another quarter of a century for Stahle to return to the site, a maze-like waterway navigable only by small watercraft. This trip would lead him farther into the Black River, to the Three Sisters swamp. After coring hundreds of old trees, he identified the 2,624-year-old cypress – nearly a thousand years older than Methuselah.

Dendrochronologist Dave Stahle, left, has been able to visit these cypress trees thanks to Charles Robbins, right, who runs a boating service in the area.

Stahle and his team have since continued their Black River research, reconstructing rainfall patterns and mapping the ancient forest. But climate change is a dangerous foe. Intensifying heatwaves, storms, flooding and droughts compound with warming temperatures to produce problems for plant growth, resilience and reproduction.

“The principal threat to our forests is people and human activity. One consequence of human activity is climate change,” Stahle said.

A little over six feet of elevation stands between the oldest-known cypress and the Atlantic Ocean. While sea level rise is increasing by two inches a decade now, it’s accelerating at a rapid pace. Sea levels are “all but certain” to rise by at least 20ft over the next 100 to 200 years. In a worst-case scenario, the world’s oldest bald cypress may already be underwater by 2080.

“With those bald cypress only two meters above sea level, that’s a really serious threat,” said Harvard Forest’s senior ecologist, Neil Pederson. “I see sea level rise as a train alarm, on a really long, overloaded train. And it’s going to take a long time to slow that train down.”

Pederson is one of the researchers behind a 2016 study that found that increasing drought conditions and extreme events of the past – which led to unusually high tree mortality rates – could be a forecast for the future.

“Even though our forests seem to change slowly over time, every once in a while these things, like black swans, these unprecedented or unforeseen events, come and change an ecosystem,” he said.

Carbon, biodiversity and coastal barriers

A 2020 study found that even though older trees can adapt to stresses and migrate as conditions change, it’s unlikely that these characteristics will be enough to ensure their survival.

Nate McDowell, earth scientist at Pacific Northwest National Laboratory and the lead author of that study, describes trees as functionally “sweating” because of warming temperatures, reducing plant productivity.

The world lost more than a third of its old-growth forests from 1900 to 2015. “All the models, all the projections, everything points in the same direction: that we’re going to lose trees,” McDowell said.

His prediction is supported by the years of recently documented increases in themortality of older trees, which researchers are identifying across the globe. Last year, more than 10% of all mature giant sequoias were killed.

When trees die, entire ecosystems are disrupted. “Once you have changes in the plant community, which is really the foundation for the whole forest, you in turn see changes in rodents, birds, even large mammals,” said plant ecophysiologist Angelica Patterson.

A 2018 study found that tree loss in the Pacific north-west can even negatively affect the climate in the eastern US. Old-growth forests act as carbon sinks, meaning they sequester and store carbon emissions, steadily accumulating carbon for centuries. If they die, that carbon is released back into the atmosphere, creating a vicious cycle that further perpetuates climate change.

Forest loss even translates to the disappearance of natural coastal barriers during storms.

A future of flooding

Locals living along North Carolina’s Black River know all about the immemorial trees. “We’re just amazed that those trees are here. The time we first heard about it, they were saying they were over 2,000 years old. And I said, “Well, they were here when Jesus was on Earth,'” said Dwight Horrell.

These cypress trees are accessible only via a ride on small boats through a maze-like swamp.

At 76, Horrell has called Ivanhoe, a rural town off the Black River, home his entire life. Climate change isn’t something he’s concerned about. Yet, dotted along a nearby shoreline are signs that suggest he should be.

Across the coastal wetlands of North Carolina, a new study found that climate change-driven sea level rise and saltwater intrusion have been killing large swaths of trees. In some cases, these “ghost forests” have even expanded inland. More than 10% of forested wetland was lost over the last 35 years in one wildlife refuge.

Charles Robbins, owner of the boating service Cape Fear River Adventures, has led Stahle through the Black River’s charcoal-colored waters for the past decade. He’s also seen first-hand how extreme flood events disrupt ecosystems and livelihoods. “There was a full foot of water on the ground and 15ft of water in the swamp,” Robbins said. “People’s houses were underwater.”

He was describing the aftermath of Hurricane Matthew – which in 2016 flooded Horrell’s parents’ house so severely they didn’t even try to rebuild. “My parents’ house was in an area that had never been flooded,” said Horrell. “The first time it flooded, it got up to about three feet off the floor. The last time, it got up to the ceiling,” he said.

Two years later, Hurricane Florence swept through, leaving a submerged town in its wake. The lowest-lying side was inundated with up to 36 inches of rain and record floods.

Everyone has since moved to higher ground, but the waterlogged shells of a few broken homes remain. “I’m telling you, it just looks morbid in that place,” said Horrell.

‘No Black River state park

The chance of dangerous flash flooding increases with intensifying storms; by 2050 North Carolina’s inland flooding events are projected to rise by 40%.

Even so, Horrell isn’t bothered by severe floods looming ahead. What he’s most concerned about is strangers disrupting his way of life. “You see how isolated this is down here? I enjoy the quietness,” he said.

In 2017, a legislative motion for a Black River state park, intended to boost tourism, caused an uproar. The following year, the North Carolina parks and recreation division recommended the state not move forward after four town halls and a petition made up of 1,300 signatures communicated the same message: those living closest to the Black River were overwhelmingly opposed.

Conservationists are split on the efforts to establish a Black River state park. It could invite more tourism and, in turn, pollution - but it could also fund conservation efforts.

Three years later, signs still frame a building bordering one of Ivanhoe’s river boat ramps; the bolded words ‘NO BLACK RIVER STATE PARK’ serving as a veiled promise.

Conservationists like Moore agree with the protesting community. It’s not climate change imperiling the survival of the oldest cypress tree she’s nervous about, but state-managed recreation, which opens the door to increased pollution, depletion of natural resources and ecosystem disturbance.

But Hervey McIver, a land protection specialist at the North Carolina chapter of the Nature Conservancy, attended those state park meetings to garner community support for the initiative. His point is simple: establishing a state park could fund and amplify conservation efforts.

“The most vocal ones were against it. There were some people who were open to it, maybe in favor of it, but not against it. But they were quiet,” McIver said. He’s optimistic that the state legislature will eventually reconsider. “Even these rural, conservative, Republican folks, they see it. They understand it, and they don’t – they know they can’t fight it.”

The Nature Conservancy has invested in the preservation of the Black River since 1989. Today, the nonprofit, alongside state conservation agencies and the NC Coastal Land Trust, owns 17,960 acres along the 66-mile Black River and its upstream tributaries, including the Three Sisters swamp.

McIver says the conservancy protects the ancient trees by acquiring the land surrounding them, which then minimizes human activity. But he isn’t sure what more can be done.

“What can you do? I’ll be long dead before the water gets that high,” McIver said, emphasizing how sea level rise is a global problem, one that requires large-scale solutions like cutting greenhouse gas emissions. “But then, you can’t stop it. I mean, if it’s going to rise, it’s going to rise.”

Environmental archaeologist Katharine Napora holding a cross section of a cypress tree.

Looking back to move forward

Some believe that question can be answered by using thousand-year-old windows into the past.

Environmental archaeologist Katharine Napora analyzed deceased eastern bald cypress trees along the Georgia coast, ranging from 65 to 1,078 years old, whose preserved remains date back to 3161BCE.

“From these ancient trees, we see that even very long-lived cypress trees in the ancient past can be killed very fast with either rising sea levels or the storm surge from hurricanes,” Napora said.

Solutions to fortifying wetlands and preserving old-growth forests, beyond curbing emissions, include creating living shorelines that act as a buffer for ecosystems from storm surges, sustainably harvesting coastal resources, lobbying for stricter regulations on companies emitting pollutants into the environment and even introducing marsh plants that double as salination sponges.

Napora believes we need to do everything in our power to preserve the Black River’s treasure trove of climate insight.

She compares the loss of old-growth forests to the burning of the Library of Alexandria, one of the greatest archives of all time. “These forests are like libraries informing us about the ancient past,” she said. “Just picture the huge amount of knowledge that would be lost if these forests no longer survive.”

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