"When Planting Trees Does More Harm Than Good"

"Note to anyone who thinks planting trees is the bees’ knees: Grasslands are important, too.

With forests disappearing at record rates and the carbon sequestration and other benefits of vegetation getting increasing visibility, tree-planting has become almost an iconic “environmentally friendly” activity. But in some cases it could do more harm than good, according to Iowa State University ecologist Joseph Veldman and colleagues.

In a paper published in the October 2015 issue of the journal BioScience, the researchers point out that the current emphasis on trees as tools for sequestering atmospheric carbon has led to a number of initiatives that encourage planting trees on grasslands or allowing forests to expand into grasslands. The U.N. Framework Convention on Climate Change’s Clean Development Mechanism, for example, offers carbon credits for foresting grasslands, the Food and Agriculture Organization of the United Nations does not distinguish for policy purposes between closed-canopy forests and grassy biomes with trees, and carbon valuation systems such as CDM and REDD+ favor forests over other types of land cover."

Mary Hoff reports for Ensia October 2, 2015.