© Tom Swetnam
This cross-section of a giant sequoia tree shows some of the tree-rings and fire scars. The numbers indicate the year that a particular ring was laid down by the tree.
This cross-section of a giant sequoia tree shows some of the tree-rings and fire scars. The numbers indicate the year that a particular ring was laid down by the tree.
Scientists reconstructed the 3,000-year history of fire by dating fire scars on ancient giant sequoia trees, Sequoiadendron giganteum, in the Giant Forest of Sequoia National Park. Individual giant sequoias can live more than 3,000 years.
"It's the longest tree-ring fire history in the world, and it's from this amazing place with these amazing trees." said lead author Thomas W. Swetnam of the University of Arizona in Tucson. "This is an epic collection of tree rings."
The new research extends Swetnam's previous tree-ring fire history for giant sequoias another 1,000 years into the past. In addition, he and his colleagues used tree-ring records from other species of trees to reconstruct the region's past climate.
The scientists found the years from 800 to 1300, known as the Medieval Warm Period, had the most frequent fires in the 3,000 years studied. Other research has found that the period from 800 to 1300 was warm and dry.
