North Carolina is known for its natural features — think the Blue Ridge Mountains or the pristine beaches of the Outer Banks. Less attention though is given to its forests. That had listener Gayle Morris wondering:
"Where in North Carolina can a person experience old-growth forests?"
In short, the answer is along the banks of the Black River in eastern North Carolina, where towering bald cypress trees have stood sentry for more than 2,000 years. WFDD's April Laissle traveled there to learn more about what these trees can tell us about the state's evolving climate.
On the River
Just off a remote road about an hour outside of Wilmington, I'm following a group of researchers past an abandoned cabin and down a gravel trail that leads to the banks of the Black River.
My companions today are dendrologists, scientists who study trees. Some have come from as far as the Czech Republic to study the ancient ones rooted under this river's murky waters. We all climb into kayaks and set off on the water.
The further down the river we get, the older the trees look. Then, as we emerge from a cypress knee obstacle course, the canopy opens and suddenly we're in Jurassic Park. Knobby, moss-covered buttress roots jut out of the water, their grey trunks giving way to branches that sit almost perfectly flat – their bushy tops have long been knocked out by storms.
Then finally, we come across The Old One, a gnarled bald cypress that, at age 2,600, is among the oldest trees in the world. It's been around since the early years of the Roman Republic, but it looks much like the rest of the trees in this area. That's because it likely isn't the oldest one here, it's just the one with the most solid trunk. The characteristic is critical for the technique used to date these trees, called coring.
Each researcher is carrying an increment borer – a kind of T-shaped manual drill. It's what they use to take samples from trees.
I watch as University of Tennessee researcher Savannah Collins-Key aims hers at a smaller tree and begins turning its top handle to drill into the trunk. She pulls out a perfectly cylindrical sample of what's inside of it and stores it in a plastic straw.
This tree, like the Old One, is solid all the way through, but there are many more in this forest that are rotted on the inside, yet still living. The more solid the core, the more comprehensive the core sample will be.
The coring process is kind of like a mosquito bite for the tree – it doesn't really hurt it. And it yields critical information.
“I sometimes call them like the first information superhighway, or the original thumb drive. There's tons of information in tree rings,” says Neil Pederson, an ecologist with the Harvard Forest who helped coordinate this trip.
“Sometimes a tree will stop growing for a year around the base of the tree. And that happens for a variety of reasons. Sometimes drought, but sometimes other things. And all that information is stored in tree rings,” Pederson says. “So we can get the age of the tree, we can get growth rates, we can get changes in growth rates. And that all tells us a little bit more information about how these trees have lived. And we can use them to make inferences about what has happened in the past.”
Pederson says in effect, these tree rings tell a story. And they can sometimes give clues about mysteries in human history too. Researchers used tree rings to determine that the worst drought in 800 years occurred the same year that the Lost Colony of Roanoke Island disappeared.
Pederson and his team are coring trees along the Black River to do what's called a climate reconstruction, specifically to learn more about how this ecosystem has historically responded to hurricanes. They're selecting several trees in this area to create what he calls “a chorus” of perspectives about what has happened here.
“The hope is that this data will be information for modelers to try to understand how future hurricanes might impact these systems,” says Pederson.
Pederson and his team will spend the next few months traveling to old-growth forests along the East Coast for the same reason.
“You put on your backpack, you get your straw, you get your increment borer and you just go looking for the oldest trees,” says Pederson. “I mean, like, don't tell anyone this, but that's what we do often. And so you're like, 'oh my gosh, I get paid to look for old trees.'”
Keys to Survival
Pederson is following in the footsteps of David Stahle, a dendrologist who teaches at the University of Arkansas. He's been studying the trees along the Black River since the 1980s. He says when he first drove along the roadway through the forest, he knew he'd hit something big.
“Old trees are like old people. They don't hide their age that well,” says Stahle. “And so we just stopped right in the middle of the road and got out of the car. And we're dumbfounded by thousand-year-old trees on both sides of the highway.”
Stahle set out to core those trees, and eventually, he came across the Old One. He says the cypresses have survived for so long in part because they're in an adverse growing environment.
“The Black River is a nutrient-poor, tannin-stained stream, a little bit acidic, you know, really kind of low in natural fertility,” says Stahle. “And so the growth rates are extremely slow.”
The environment was poor enough to hinder growth, but not quite bad enough to kill them. Their age is what helped them dodge the logging bullet, Stahle says.
“They're very old trees. From a logging point of view, timber production point of view, they are decrepit, over mature, pecky and heart rotten,” says Stahle. “And those are all negatives when it comes to board footage.”
Major storms also couldn't knock these trees out. Stahle says that's because as harsh winds blow in, the trees hold onto each other under the water.
“And so if you're going to blow it over, you've got to blow the entire forest over,” says Stahle. “They'll snap off, especially a hollow cypress will snap off in a hurricane. But rarely will you see them uprooted.”
The continued longevity of these trees is something Stahle worries about though. He says human actions can seriously impact this ecosystem.
“All kinds of industrial activity could be installed within the drainage basin of the Black River that could impact water quality, and, in fact, has impacted water quality of the Cape Fear and her tributary. So, you know, we know this story, right, we know the story of the anthropogenic climate change, the human impact on the environment in North Carolina, and Arkansas, and elsewhere in the United States. And it's just not a trivial problem.”
Stahle says his research has also revealed insights into what the future may hold for these ecosystems if more isn't done to address climate change. Tree ring data suggest that it's only gotten wetter in the modern era due to warming temperatures. And with the sea level rising and the forest just two meters above it, these trees could soon be in dire straits.
“With uncontrolled anthropogenic climate change, you know, they're going to be ghost trees in the future,” says Stahle. “Now, that's not tomorrow. It's maybe not for 100 years, maybe 500 years, but, you know, I'm confident we're gonna have to get a handle on the energy crisis.”
Stahle says he has hope though. He sees enormous pressure, economic and otherwise, to address climate change.
“But those things are hard to turn around,” he says. “So you don't want to mess with Mother Nature. And we are.”
Stahle continues to advocate for conservation both at the state and federal levels. He plans to return to this river this month in search of more ancient trees, and the stories they have yet to tell.