Planting trees in the wrong place will heat the planet

Planting trees in the wrong place can actually contribute to global warming, scientists said on Tuesday (March 26), releasing a new map identifying the best places to plant them. reforest and cool the planet.

Trees absorb carbon dioxide, and restoring degraded forests or planting young trees to increase forest cover is a tool in the fight against climate change.

But in some cases, more trees mean less sunlight is reflected from Earth's surface and the planet absorbs more heat , according to a study just published in the journal Nature Communications on April 26. /3.

Kenya has a national tree planting holiday on November 13 every year. (Photo: AFP).

Susan Cook-Patton, one of the study's co-authors, said: ' There are some places where replanting trees will lead to negative climate outcomes '.

Scientists previously understood that restoring tree cover leads to changes in "albedo" — that is, the amount of solar radiation that is bounced back off the planet's surface, she said. There's nothing to prove that yet.

Using the new maps, researchers were able to look for the first time at the cooling effects from trees and the warming from reduced albedo.

The researchers found that projects that did not factor albedo into the equation overestimated the climate benefits of planting more trees by 20 to 80%.

Tropical environments such as the Congo Basin have high carbon storage capacity and little change in albedo. (Photo: AFP).

But the new map the researchers released also provides tools to help policymakers determine where best to allocate scarce resources to create maximum climate impact. , said Cook-Patton, senior forest restoration scientist at The Nature Conservancy.

She said: 'There are also many places where restoring tree cover is a great idea to respond to climate change. We're just trying to help people find those spots.'

The Albedo terrain has the highest albedo with high albedo levels reflecting up to 90% of the sun's energy. Those are icy areas of the world with snow and ice as clean as a mirror.

It is one of the Earth's main cooling agents. Together with land and oceans, it absorbs excess heat and emits greenhouse gases that contribute to global warming.

Plant mangrove trees on Paris Island to slow erosion caused by rising sea levels. (Photo: AFP)

The study shows that many countries have pledged to plant billions of trees as a bulwark against global warming, but not all efforts are equally effective for the planet.

Wet, tropical environments like the Amazon and Congo basins have high carbon storage capacity and little change in albedo , making them ideal locations for restoring forest cover.

"The opposite happens in temperate grasslands and tropical grasslands ," Cook-Patton said.

Even projects in the best locations can provide 20% less cooling than estimated when accounting for changes in albedo, she said.

But she emphasized that restoring forests brings undeniable benefits to people and the planet, such as supporting ecosystems and providing clean air and water, among many others.

She said: 'We really don't want our work to become a criticism of the movement. But, we cannot plant trees everywhere. We don't have enough money, time, resources, people or seedlings."

She added: 'And so it's really about making the most of limited investments and getting the biggest climate return on every hectare of investment' .