Tree ring‐based reconstruction of annual precipitation in the south‐central United States from 1750 to 1980

Abstract

A 231‐year reconstruction of annual precipitation, from 1750 through 1980 A.D., was developed from 10 tree ring chronologies (9 post oak, Quercus stellata, and 1 white oak, Q. alba, series) in the south‐central United States. Straight line regression was used to calibrate regionally averaged precipitation with ring width data, and the derived reconstruction was verified with independent climatic data and historical evidence. A variance trend in the tree ring data, which may have resulted from nonclimatic factors, was removed. The reconstructed precipitation series indicates that (1) a drought which appears to have been more severe than any in the instrumental record occurred about 1860 and (2) severe and prolonged droughts comparable to twentieth century events have occurred at roughly 15‐ to 25‐year intervals throughout the past 231 years. It follows that serious droughts in the south‐central United States could be expected to recur even in the absence of projected CO2‐induced warming.