Why it matters
Carbon growth spurt
5th January 2008
Doubling atmospheric carbon dioxide speeds up tree growth by about 20 per cent - but probably not in the long run
Higher levels of atmospheric carbon dioxide boost tree growth - but likely just for a few years
According to a study by the U.S. Department of Energy, carbon dioxide in the atmosphere could change the composition of microbes in the soil – and actually help plants grow faster. On one stand of aspen trees in Wisconsin, ecologists increased the level of carbon dioxide in the air to about 560 parts per million. This is about twice the current atmospheric level, or about the level predicted for 100 years from now if current trends continue, which they discovered increased the bacteria that break down leaf litter and release nutrients into the soil, boosted fungi that live on plant roots and help them grow, and decreased fungi that cause plant disease.
Many studies have shown that plants increase their growth in high carbon dioxide. In the case of the Wisconsin aspen, by about 20 per cent. What scientists don’t know is whether plants can keep this up in the long run.
Daniel van der Lelie, who headed the DOE’s study, is skeptical about ongoing plant growth in a heavy CO2 environment. Their initial burst of growth could deplete the soil of key nutrients, particularly nitrogen. But this study does imply that with some help from soil bacteria and fungi such growth could be sustained, though probably for just a few years.
Published in The Green Report in The Globe and Mail
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