There's a specific stand of bald cypress trees along the Black River in North Carolina that are some of the oldest trees in the country. Locally known as the Three Sisters Swamp, there are several trees in the group known to be more than 1,000 years old.

But researchers recently discovered a bald cypress (Taxodium distichum) in the swamp that's at least 2,624 years old. According to their study, published in the journal Environmental Research Communications, the discovery revealed bald cypress as "the oldest-known wetland tree species, the oldest living trees in eastern North America, and the fifth oldest known non-clonal tree species on earth."

(Non-clonal trees mean the trunk is the same age as the roots. Clonal trees originate from the same ancestor and often live for tens of thousands of years.)

According to the researchers, only individual trees of Sierra juniper (Juniperus occidentalis) at 2,675 years, giant sequoia (Sequoiadendron giganteum) at 3,266 years, alerce (Fitzroya cuppressoides) at 3,622 years, and Great Basin bristlecone pine (Pinus longaeva) at 5,066 years old are known to live longer than the Black River bald cypress.

How old is old?

To understand how old this tree really is, Smithsonian explains it was alive "when Nebuchadnezzar II built the Hanging Gardens in Babylon, when the Normans invaded England, and when Shakespeare first set quill to paper."

Lead author David W. Stahle, a University of Arkansas scientist, says, "It was like walking back into the Cretaceous. It was essentially a virgin forest, an uncut old-growth forest of 1,000 to over 2,000-year-old trees cheek to jowl across this flooded land."

Although the bald cypress trees are in a protected area owned by The Nature Conservancy, they are still imperiled by continued logging and water pollution, as well as sea level rise.

The researchers conclude: "To counter these threats, the discovery of the oldest known living trees in eastern North America, which are in fact some of the oldest living trees on earth, provides powerful incentive for private, state, and federal conservation of this remarkable waterway."