Earth's biggest tree rings tell fiery tales

[Still Waters]

Fallen giant sequoias reveal a 3,000-year-old history of fire and drought.

Using huge chainsaws and strong backs, the largest trees in the world are finally giving up their 3,000-year record of fires and droughts. No trees, however, were harmed in the making of this fire history.

"We only used dead trees," emphasized tree ring researcher Thomas Swetnam of the University of Arizona. Swetnam led the study that was reported in a recent issue of the journal Fire Ecology. "We spent multiple years collecting the wood and hauling it back to Tucson.

The giant sequoias in California's Sequoia National Park are far too thick to be cored for the extraction of the pencil-thin cores typically used by tree ring researchers. So the authors of a new report on tree ring evidence of past droughts and fires used all sorts of other tools to slice and dice 52 giant dead and fallen sequoias, lug the pieces back to roads by hand. Then they spent years piecing together the valuable history in their laboratories.

Read more...