When Planting Trees Hurts the Environment

http://www.thenation.com/article/when-planting-trees-hurts-the-environment/

But a close look at the Uruguayan experience reveals that planting a tree is not always a good thing. It depends on what species gets planted and where, who plants it, and who owns the land.
Thus, even with the best of intentions, without local land ownership and a mechanism to ensure that each tree-planting project under the umbrella of Initiative 20×20 is proceeding as planned, the unintended consequences could be severe.

At La Cascada, María Muñoz objected to planting trees. She was concerned they might drain the estate’s groundwater, invade the natural grassland, and erode the topsoil. But, more than anything, she worried about destroying the landscape.

“If tomorrow, I want to look out and all I can see are trees… she didn’t really like that idea,” Pancho explains. The idea of change “worried Mamá the most, because she was the one who enjoyed the view the most.”

<snip>

But not everyone approves. A tree farm isn’t a forest, some environmentalists argue. While diverse, native forests sequester carbon in the trees, the undergrowth, and the soil, tree farms sequester carbon only in the trees themselves. In that case, “the only way to add to the carbon stock is by adding land,” says Matt Palmer, an ecologist at Columbia University—and “you’ve set yourself a pretty low ceiling for what sequestration is possible.” Furthermore, environmentalists argue, the focus on a global calculation of atmospheric carbon can obscure local effects on ecosystems, economies, and families.

Just because you can plant a tree somewhere doesn’t mean you should,” Palmer concludes.