sexta-feira, 5 de fevereiro de 2016

Aquecimento global

Planting The Wrong Trees in Europe Made Climate Change Worse: Why Reforestation Isn't That Easy

You’ve heard it before: Deforestation is a major contributor to climate change. To put it simply, trees store carbon, preventing it from entering the atmosphere—which means there are fewer greenhouse gases screwing with Earth’s climate. And, broadly speaking, that’s true. Planting trees is good for the planet. But it’s more complicated than that. Research published this week took a fine-toothed comb to the issue of forest management and reforestation. And the researchers found a major tangle: It turns out we’ve been planting the wrong trees, for a long time. And that choice of trees has actually been making climate change worse.
In a paper published Thursday in the journal Science, researchers looked at the history of reforestation in Europe. As of 2010, 85 percent of forests on the continent were managed by humans, they write. And for nearly 250 years, forest managers have tended to prefer reforesting with more “commercially valuable” and fast-growing species of trees, like Scots pines, Norway spruce and beech trees. Two of those three “preferred” species are conifers; more often than not, they’d be used to reforest an area where broad-leaved trees once stood. According to the researchers, almost 400,000 square miles of broadleaf forest have been replaced by conifers since roughly 1850.
The conifers have needles instead of leaves, and the pigment of their needles is much darker than leaves would be. That means they absorb more solar radiation, rather than reflecting it back up to space, than leaves would. That causes the temperatures in these forests to rise, ultimately adding to warming, rather than reducing it.
Mais

Nenhum comentário:

Postar um comentário