In a report entitled Evidence for a Recent Increase in Forest Growth, Sean M. McMahon, Geoffrey G. Parker, and Dawn R. Miller document an increase in the rate of growth of fifty-five mixed hardwood plots at the Smithsonian Environmental Research Center, 2600 acres on thean increase in the rate of growth of fifty-five mixed hardwood plots at the Smithsonian Environmental Research Center, 2600 acres on the edge of Chesapeake Bay in Maryland. The land-use histories of the plots were known and the stands ranged in age from 5 to 250 years. Parker and associates tracked trees over a period of twenty-two years and found that ninety percent of the stands grew two to four times faster than the expected growth rate caused by natural recovery. The rapid accumulation of biomass is apparently a result of climate change. During the years of measuring trees, CO2 levels at the Research Center grew twelve percent, the mean temperature increased almost three tenths of a degree, and the growing season became 7.8 days longer. The authors do not anticipate that the accelerate growth rate will continue indefinitely and wonder how its slowing down will affect CO2 levels. Their report, which adds to accumulating evidence of accelerated tree growth at a variety of locations, was published February 2 in the online Proceedings of the National Academy of Sciences (PNAS).
Sources in addition to the report are
David A. Fahrenthold, “Climate Change’s Impact on Forests Being Measured via Expanding Tree Trunks,” The Washington Post, February 20, 2010;
and Tina Tennessen, “Smithsonian Ecologists Discover Forests Are Growing at a Faster Rate,” Science at the Smithsonian, posted February 1, 2010 at http://smithsonianscience.org/2010/02/forests-growing-at-a-faster-rate .
–Mary Byrd Davis
Copyright © 2010 by EcoPerspectives
Tags: climate change, Geoffrey Parker, SmithsonianEnvironmental Research Center, tree growth
