A team of scientists lead by Jeffery Chambers of the University of California, Irvine, studying the effects of CO2 on tree growth, has predicted that an atmosphere enriched with 50% higher levels of CO2 over the next century could encourage a 25% spurt in growth in the woody fibre in large, slow-growing trees. The researchers also found that after enrichment stopped, large, slow-growing trees took decades to fall back to their original growth rates.
“A number of studies have indicated that Amazon forests are gaining mass,” says Chambers. But these findings are controversial, and it is unclear whether carbon dioxide is stimulating the growth. Working out the forests’ behaviour, says Chambers, “will probably take many more years of research.”
The Chambers team points out that Amazonian trees have a very long life-span, of an average 175 years, which means that the stored carbon dioxide would not be released until the 22nd century. However, the researchers point out that forests should not be used to clean up after human activity. “Controlling the increase in atmospheric carbon dioxide will require substantial reductions in fossil fuel emissions,” they say.