Forests May be Storing Less Carbon Than Expected with Land Use Changes

As carbon is emitted into the atmosphere from manmade emissions, forests are taking up a large part of the burden. Now, though, scientists have found that carbon accumulation levels in the southeastern U.S. may be slowing due to forest dynamics and land use changes.

"Future land transitions are uncertain but relatively small changes in afforestation form agriculture resulted in substantial decrease in accumulation rates," said John Coulston, one of the researchers, in a news release. "While tree-cutting did cause a decrease, overall forest growth was much greater, partly due to the rapid growth of younger forests."

The researchers isolated the impacts of forest disturbances. These included fire, disease, and cutting as well as the impacts of land use changes. The scientists examined permanent monitoring locations across the southeast, making this study one of the most thorough carbon studies completed.

The scientists found that the aging of forests in the region was a significant force behind potential slowing accumulation rates as growth rates are typically lower for older forest. More specifically, the study found that forests were fairly resilient to natural disturbances caused by weather, insects, diseases and fires. These disturbances reduced carbon accumulation rates, but the losses were compensated by subsequent regrowth and storage of dead material on site.

"These findings highlight the need for careful assessments of policies that affect forest management and land use changes in rural areas of the southeast," said David Wear, the project leader. "Continued forest carbon accumulation in the region is highly sensitive to land use transitions."

The findings are published online.

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