Forests could be buffer against climate change

Forests may be a potential buffer against global warming by absorbing a portion of projected increases in atmospheric carbon dioxide, say researchers from West Virginia University.

Researchers have found that pine trees in a piedmont North Carolina forest grew at a faster rate when carbon dioxide levels were increased by 50 percent.

“I’m not saying you should go out and plant more trees, but it’s good to have the forest there because it could be a potential buffer against climate change,” said Dr. Richard Thomas, an assistant professor of biology in WVU’s Eberly College of Arts and Sciences.

The purpose of the research project is to determine how an intact forest responds to increased atmospheric carbon dioxide and to see if plants can absorb enough carbon dioxide to slow the increase of greenhouse gases in the air. A substantial reduction could partially offset potential climate change resulting from increased carbon dioxide levels.

Scientists have been experimenting with plants and how they react to increased levels of carbon dioxide for the past 20 years, Thomas said. Prior research, however, was confined to studying plants in growth chambers and greenhouses.

“This is the first time a forest ecosystem has been manipulated with elevated levels of carbon dioxide,” he said.

Thomas and his fellow researchers are conducting their experiment in a loblolly pine forest at Duke University. In this forest, they have installed a gas-delivery system that includes a holding tank and several towers. Carbon dioxide travels from the tank to the towers through above-ground lines. It is then discharged into the air through pipes at the tops of the towers, fumigating the forest without disturbing its ecosystem.

The researchers control the amount of carbon dioxide released from the towers, discharging the gas at current levels and at elevated amounts projected for 2050. After two years of comparing the effects of the two gas levels on the ecosystems, they have found that the growth rate of the pine trees is about 25 percent greater in the areas with increased carbon dioxide levels.

“We had predicted a much smaller effect,” Thomas said. They have also calculated that if all forest ecosystems in the world reacted similarly, the forests would absorb about 50 percent of the projected carbon dioxide emissions from fossil fuels in 2050.

Thomas cautions that the results are not conclusive, noting that not all forests are in as temperate an environment as the one at Duke and not all trees grow as fast as the loblolly pine.

The findings are significant, nevertheless, Thomas added. “This means forests are important in the carbon balance globally,” he said. “What this suggests is that forests will to some degree offset the increases in atmospheric carbon dioxide that humans are releasing by burning fossil fuels.”

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