Trees that grew in Antarctica millions of years ago had a growth pattern much different than modern trees, according to a new fossil study reported during the Geological Society of America meeting.
Although Antarctica is now much too cold to support vegetation, it hasn’t always been: The fossil record indicates that plants thrived on the now-icy continent from 400 million to 34 million years ago, says Patricia E. Ryberg, a paleobotanist at the University of Kansas in Lawrence. Indeed, she notes, lush forests covered the landscape during some parts of that interval, even though Antarctica sat at or near the South Pole then, as it does today.
But those ancient Antarctic trees grew nothing like today’s trees do, Ryberg reported October 5 in Houston during the annual meeting of the Geological Society of America. Modern trees living in temperate climates have annual growth rings no wider than 2 millimeters. But some samples of the well-preserved fossils of trees that covered Antarctica about 255 million years ago during the Permian have growth rings close to 10 millimeters wide. Trees that lived about 237 million years ago, during the Triassic, have growth rings as wide as 6.8 millimeters, Ryberg and University of Kansas colleague Edith L. Taylor found.