Planting trees in wrong places heats the planet: study

Planting trees in the wrong places can actually contribute to global warming, scientists said yesterday, but a new map identifies the best locations to regrow forests and cool the planet.

Trees soak up carbon dioxide and restoring areas of degraded woodlands or planting saplings to boost forest cover is one tool in the fight against climate change.

But in some cases, more trees mean less sunlight is reflected back from the earth's surface and more heat is absorbed by the planet, according to a study in the journal Nature Communications.

"There are some places where putting trees back leads to net climate negative outcomes," Susan Cook-Patton, one of the study's co-authors, told AFP.

Scientists had already understood that restoring tree cover led to changes in albedo -- the amount of solar radiation bounced back off the planet's surface -- but didn't have the tools to account for it, she said.

Using new maps, researchers were able to consider, for the first time, the cooling effect from trees and the warming caused by decreased albedo. They found that projects that didn't factor albedo into the equation overestimated the climate benefit of additional trees by between 20 to 80 percent.