NPR Series on Fire History based on LTRR Work
A documentary that has just appeared on NPR is largely based on the Laboratory of Tree-Ring Research's work that shows how fire suppression efforts in the past century have paradoxically encouraged severe wild fires in the American South-West. Trees can accumulate long records of past fires in the form of sequences of scars (where a fire has damaged the tree but not killed it). Tree-ring dating can determine the years (and sometimes even the seasons) where the scars formed, showing that in many cases fires were more common but less severe before recent fire suppression.
For a full summary, and a link to the video and audio versions, see the article “How The Smokey Bear Effect Led To Raging Wildfires” by Christopher Joyce on the NPR web site.