In other scientific news of the day, trees might not be a climate change magic bullet after all, according to a study published in today’s edition of Nature. Trees and shrubs have been regarded as an ideal carbon sink (meaning they absorb excess carbon dioxide, reducing the concentration of the greenhouse gas in the atmosphere) and therefore an effective means to fend off global warming. President Bush has even proposed tax incentives for farmers who plant trees. But scientists from Duke University found that in wetter areas, trees are less effective carbon sinks than the native grasslands they have replaced throughout much of the Western U.S. The study said that replacing grass with shrubs and trees can actually decrease the amount of carbon stored in organic material in the soil, potentially offsetting gains achieved above ground. Daniel Becker, director of the Sierra Club’s global warming and energy program, said the study would help dispel the notion that humans can plant their way out of the climate crisis.