May 9 (UPI) -- Scientists have documented some of the oldest trees in the world inside wetlands along the banks of North Carolina's Black River.
According to a new study published Thursday in the journal Environmental Research Communications, the bald cypress trees, one of which is at least 2,624 years old, are the oldest living trees in eastern North America and the oldest wetland tree species on the planet.
Originally, researchers from the University of Arkansas were attempting to reconstruct the climate conditions in the Southeastern United States over the last few thousand years. To do so, scientists drilled cores into the trunks of the bald cypress living along the banks of the Black River. Tree rings can communicate temperature and precipitation records.
The cores revealed extreme droughts and flooding during colonial and pre-colonial times. While studying the tree rings and analyzing radiocarbon data, the research team realized they had happened on an especially old stand of trees.
"It's an amazing coincidence that the oldest known living trees in eastern North America also have the strongest climate signal ever detected anywhere on Earth," research leader David Stahle, a professor of geosciences at Arkansas, told Smithsonian Magazine. "The best correlations we've ever seen are with these trees. Why that is I don't know. They're incredibly old and extremely sensitive to climate, especially rainfall.
Stahle knew the Black River wetlands housed old trees. He had previously documented a 1,700-year-old bald cypress during a 1988 survey. But his latest research efforts showed the ancient forest houses even older trees.
Stahle's work in the region led to the protection of the forest, an intact ecosystem that stretches for 65 miles along the edges of the Black River. The Nature Conservancy bought and protected 16,000 acres of the forested wetlands.
Originally an archaeologist, Stahle is one the world's leading experts in the field of dendrochronology, the study of tree rings. He has been leading expeditions along the banks of the Black River since 1985, but only recently visited the remote portion known as the Three Sisters, where a trio of slow-moving river channels converge. There, Stahle and his colleagues found the oldest Black River bald cypress yet.
"The area of old-growth bald cypress was 10 times larger than I realized," Stahle said in a news release. "We think there are older trees out there still."
Previous bald cypress tree cores have helped him trace the timing of an extreme drought that began 1587 and lasted two years. The drought coincided with the collapse of the lost Roanoke Colony. Stahle plans to continue using the ancient trees to unlock the secrets of North American's climate history.