CO2 Boosts Tree Growth Rate Longer Than Previously Thought

Elevated CO₂ concentration increases production and growth of developing North American forest communities, according to a new study in Ecology Letters. Science Daily reports that throughout the 12-year study, trees exposed to higher levels of CO₂ grew at a higher rate than those exposed to normal levels of CO₂. Previously, scientists expected that increased growth rates would last for only a short time, limited by the trees’ ability to extract nitrogen from the soil. In fact, the trees grew more small roots and microbes increased the rate of nitrogen release from decaying leaves. The researchers also tested the effects of ozone (the primary constituent of smog) on tree growth and found that despite initial declines in tree growth, by the end of the study the rates were the same for both exposed and unexposed trees.