Global tree-planting push threatens African grasslands, warns report

A campaign to plant trees across Africa risks “double jeopardy” because it will damage ancient grassland ecosystems that absorb carbon dioxide while failing to fully restore depleted forests, according to research.

Half the land earmarked for regeneration by the 34-country African Forest Landscape Restoration Initiative (AFR100) is in savannah or other non-woodland areas, says a paper published in Science on Thursday.

The study will intensify debate on whether global tree-growing projects will help mitigate climate change and other environmental damage. Such initiatives have attracted investment from sources including western governments and philanthropic bodies such as the Bezos Earth Fund established by Jeff Bezos, Amazon’s founder.

“There is a vast area of non-forest across Africa that is earmarked for restoration, principally through tree planting,” said Catherine Parr, a co-author of the paper and an ecologist at Liverpool, Pretoria and Witwatersrand universities. “The focus solely on forests and trees is highly problematic for these non-forest systems.”

The AFR100 project seeks to restore at least 100mn hectares of degraded land — an area the size of Egypt — in Africa by 2030, with big plans in countries including Cameroon, Ethiopia, Mali and Sudan. The initiative’s backers include the German government, the World Bank and the non-profit World Resources Institute.

But about half of the approximately 130mn hectares that African countries have committed to restore through AFR100 is earmarked for non-forest ecosystems, principally savannahs and grasslands, according to the paper.

The researchers said they could only find evidence of one project — in Kenya — dedicated to restoring grasslands. More than half a dozen countries with no forest cover have made AFR100 pledges, including Chad and Namibia.

“Ultimately, the right trees and the right number need to be planted in the right place,” the paper said, adding that many savannahs and grasslands are inaccurately classified as forest areas in international data. “[U]ntil the definition of forest is revised, there will always be the double jeopardy of afforestation of ancient grasslands and deforestation of virgin forest.”  

AFR100 defended the initiative, which it said covered both forested and non-forested degraded lands. One of the AFR100’s core principles was that native grasslands should not be converted into forests, said the World Resources Institute, which is a technical partner of the project.

Many AFR100 restoration projects involved adding trees to existing croplands to improve soil fertility, increase water retention and reduce topsoil erosion, the institute added.

The Bezos Earth Fund, a financial backer of AFR100, did not immediately respond to a request for comment.

The dispute over the research highlights growing friction over pledges by philanthropists and corporate leaders to plant a trillion trees worldwide. These ambitious plans face obstacles including potential shortages of available land suitable for planting. Other questions concern how effective newly planted trees are at locking in significant amounts of carbon dioxide — and how vulnerable they are to risks such as forest fires.

“There’s such a big focus at international level on deforestation, but the level of sophistication and understanding about ecosystems writ large is really low,” said Alex Reid, a policy adviser on nature and finance at Global Witness, a non-profit group. 

Some scientists and conservationists argue that it is better to focus on preventing deforestation, by creating incentives to retain woodland areas. Greenhouse gases released by deforestation make up about 11 per cent of global emissions, according to the Intergovernmental Panel on Climate Change. 

Highly forested countries such as Gabon and Suriname have struggled for decades to attract enough investor interest in nature protection, including through the issuance of carbon credits. 

“It’s insane to put too much effort on reforestation when we’re [still] cutting down rainforests at a high rate,” said Ed Mitchard, professor of global change mapping at Edinburgh university and chief scientist at Space Intelligence, which measures natural carbon stocks using satellites.

He said most tree-planting initiatives were “tinkering round the edges”, given that older natural forests store more carbon than younger trees. 

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