Introducing too many trees into the African savannah can prevent small plants from accessing sunlight, which can affect the animals that eat them
Karine Boukey/Alamy
Ambitious tree-planting projects aimed at restoring Africa's forests could inadvertently harm grasslands and savannahs by providing too much shade. This can interfere with photosynthesis in small plants, which can have knock-on effects on other parts of the ecosystem.
In 2011, the German government and the International Union for Conservation of Nature launched the Bonn Challenge to restore 350 million hectares of degraded or deforested land around the world by 2030. As part of this effort, the African Forest Landscape Restoration Initiative (AFR100) was formed, with 34 countries across the continent pledging to reforest his 133.6 million hectares of land.
However, this has raised concerns about how Africa's other major ecosystems will be affected. You can learn more about kate parr Researchers at the University of Liverpool in the UK compared the area of forest restoration efforts in the AFR100 countries with the area of naturally forested areas.
In 18 of these countries, the pledged area was found to exceed the actual forest area, so non-forest habitats must also be included in the pledged area.
Of the 133.6 million hectares committed to reforestation across Africa, 70.1 million hectares are comprised primarily of non-forest ecosystems such as grasslands and savannahs. “It's the size of France, it's huge,” Parr said.
The researchers also found that 52 per cent of projects already underway are located in grasslands or savannahs. Approximately half of these are agroforestry projects. These include planting trees on agricultural land, which tends to be non-forest areas consisting of non-native species with low overall species diversity.
“Trees are great individually, but when you get a lot of them together, they can really change the ecosystem,” Parr says.
In open, grassy ecosystems, trees typically grow in a sparse pattern. Crowding of trees through mass planting can greatly reduce access to sunlight and can damage small plants. This has a knock-on effect on animals such as zebras that eat these plants.
Many of the countries involved receive funding to carry out afforestation projects, so there is an economic incentive to plant more trees, Parr said. “There is also a lack of awareness that these ecosystems are being harmed by tree planting,” she says.
Mr Parr hopes those responsible for tree-planting operations will consider the broader impacts of where they are planted, working with local communities to ensure people's livelihoods are not affected.
Jessica Gurevich A professor at Purdue University in Indiana said: “This is a worrying wake-up call for NGOs.” [non-governmental organisations], national and international restoration efforts, and a misguided “let's plant a tree” public reassured that these efforts must be more tightly controlled and evidence-based. Masu. ”
AFR100 had not commented at the time of publication.
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Source: www.newscientist.com
