A North Carolina Swamp Unveils An Ancient Forest And Clues To Our Climate History

May 10, 2019

In a swamp on the Black River, researchers have uncovered an ancient forest filled with dozens of trees that date back millennia.
Credit Will Michaels / WUNC

A swamp on the Black River near the town of Ivanhoe, North Carolina has been a long-running fascination for researchers.

Decades ago, they identified dozens of bald cypress they believed were part of an ancient forest, but until now, they weren't sure how long these trees had been living in this remote corner of Bladen County. A recently published research paper has revealed the trees to be among the oldest in the world.

Angie Carl, who manages part of the river for The Nature Conservancy, paddles out through the dark, sweet-tea-colored water that inundates the forest. She weaves a kayak through dozens of cypress roots that poke through the surface of the water like stalagmites. In a clearing, the small dense trees suddenly become much bigger.

"You can start to see ancient [tree] tops now. Look how big the buttresses are," she says.

Carl stops at the base of a thick cypress about 60 feet tall.

Ancient cypress trees sprout out of the ground in a swamp on the Black River. Their "knees," a part of the root system, emerge from the waters around the ancient grove.
Credit Graham Youngblood / WUNC

"We're underneath one of the multi-millennial aged bald cypress trees at Black River, North Carolina..." University of Arkansas geosciences professor David Stahle says from an adjacent kayak.

Stahle led a study published this week in the journal Environmental Research Communications about these trees. He honed in on tree in particular and used radio-carbon dating, took a core sample, and counted the rings to reach his conclusions.

"And it's at least 2,624 years old. So, the inner ring is 605 B.C. It's amazing."

That date makes the cypress the fifth oldest living tree in the world, a tree older than Christianity.

"And he looks old,” said Stahle. “He's got a busted out canopy, he's re-sprouted smaller limbs to survive. He's got areas where big, heavy branches have been ripped out and soil has accumulated, and he has a little garden of geraniums growing out of the side of a busted out hollow."

What makes the discovery more surprising is that it's in the wetlands of coastal North Carolina.  The oldest trees on record are in places like Nevada, California and Chile; dry, temperate places. But Stahle says the cypress can tolerate the harsher conditions in the Carolinas.

"We think it has to do with these nutrient-poor acidic swamp water conditions. This is Black River, North Carolina. The water is the color of tea ... So the trees grow slowly and achieve remarkable age. And all of those things contribute to the exclusion of most competing tree species."
 

A close-up shot of the complex and mysterious root system of an ancient cypress forest on the Black River.
Credit Graham Youngblood / WUNC

Stahle studies trees like these to get a better idea of climate history. Each ring of the tree's core represents a growing season, and tiny variations give researchers an estimate of each year's rainfall. That's more than 2,000 years of data that can show what is natural when it comes to droughts and floods, and how humans are disrupting that.

"So mankind is now having a detectable effect on the global climate, and regional climate variability as well, and so we want to put that anthropogenic forcing in a longer-term perspective,” says Stahle.

Angie Carl paddles back upriver away from the ancient grove. This quick trip is just a tour. The Black River is a navigation channel, but it's hard to access and not fully open to the public. She says she hopes it will be one day so that North Carolinians can experience this historic site for themselves.

"What did someone call it? The Sistine Chapel of the Cypress Swamps? It is."

Except it has about 2,000 years on Michelangelo.