Friday, March 20, 2015

Drought History in Tree Rings

Tree rings can be used to study drought history of particular regions.  The lighter parts of a tree's rings correspond to its growing seasons each year, and multiple close-together dark lines signify a drought period.  Giant sequoias can live to be over 3,000 years old, so cross sections of their trunks can show centuries of drought history.  Hughes, 1992 shows the findings of a research team that studied giant sequoias in the Sierra Nevada mountain range and produced a climate history of the years 101 BC to 1988 AD.  The past century has had a low drought frequency so far.  It would be interesting to see how the current drought in California would look compared to other droughts recorded by these trees.
Tree rings from a giant sequoia

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