Here is an article about a study of tree rings which reveals important information about past climate and fires. But what I would like to know is, did anybody ask why these trees are now dead?
"To study tree rings, researchers generally take a pencil-sized core from a tree. The oldest rings are those closest to the center of the tree. However, ancient giant sequoias can have trunks that are 30 feet in diameter -- far too big to be sampled using even the longest coring tools, which are only three feet long.
To gather samples from the Giant Forest trees, the researchers were allowed to collect cross-sections of downed logs and standing dead trees, he said. It turned out to be a gargantuan undertaking that required many people and many field seasons."