Planting trees can reduce carbon emissions, but may also cause an ecological crisis! New research suggests that large-scale reforestation programs in Africa may misidentify "savannas" and grasslands as forests and plant trees in these areas. More trees in the grassland may make herbivores have less food or be more vulnerable to attack, affecting the balance of the ecosystem.
Study: Misclassification of forests and planting of wrong trees leads to ecological crisis
AFR100 is the abbreviation of African Forest Landscape Restoration Initiative. This initiative was launched at the Paris Climate Conference in 2015 to restore [1] the landscape of 100 million hectares of land in Africa by 2030. Projects include afforestation, promoting permaculture, and reducing chemical fertilizers. Over the past seven years, the participating countries have increased from 21 to 34, and the land committed to join the action has also increased to 130 million hectares.
However, a study published in the journal Science in February pointed out that in the AFR100 tree planting plan, up to 52% of land is not forest, but sparse forest grassland. Errors in definition and classification may lead to the planting of large numbers of trees on grasslands, affecting an area of more than 60 million hectares, an area larger than France.
The study was published jointly by British and Dutch academics. Lead author Kate Parr, a professor in the Department of Tropical Ecology at the University of Liverpool, UK, pointed out: "Ecosystem restoration is necessary, but different methods must be used in different ecosystems."
He said the definition of forest should be revised as soon as possible to avoid confusing sparse grasslands and forests. The increase of trees will be detrimental to the ecological integrity of open forest grassland.
The Guardian reported that according to the Food and Agriculture Organization of the United Nations (FAO), land with an area of more than 0.5 hectares, trees with a height of more than 5 meters and a canopy coverage of more than 10% meets the definition of "forest". Therefore, open forest grasslands may be regarded as forests and become targets of tree planting programs.
Open forest grasslands are home to rhinos, wildebeests, giraffes and other herbivores. They must always be alert to avoid predators. The vast field of vision helps you detect danger, escape quickly, and increases your chance of survival. Too many or too few trees can be a serious problem for survival.
There are other problems with planting trees on open forest grassland. The tree canopy blocks sunlight, and the vegetation on the ground changes accordingly. Herbivores have less "grass" to eat and the "grass species" have also changed, which will have serious consequences.
AFR100: Plan to focus on agroforestry
The latest research not only points out the consequences of forest classification errors, but also finds that up to 60% of the trees planned to be planted by AFR100 are not native species and may harm the local ecology.
"Planting the wrong tree" is not a new problem. Deutsche Welle reported in 2021 that Kenya had introduced mesquite trees (scientific name: Prosopis juliflora) to reduce sandstorms and provide wood for cooking or building animal stables. However, heavy rains in 1997 caused the mesquite to spread rapidly and become a strong alien species, crowding out the space of native plants and leaving local animals with insufficient food.
In response to the serious accusations made by scholars, "The Verge" specifically asked AFR100. AFR100 clarified that AFR100's plans cover a variety of types, and it is not correct for scholars to count all committed land as areas that will be planted with trees in the future.
One of the sponsors of AFR100, the World Resources Institute (WRI), also stated that "the vast majority" of AFR100's projects are agroforestry (agroforestry). Planting trees on farmland can help improve soil fertility and soil and water conservation, and Can reduce soil loss. But Pal countered that planting trees on non-forest land does not constitute ecological "restoration."
Social giant Meta and the Bezos Earth Fund have both funded AFR100. When asked about the question of "planting the wrong tree", the Bezos Earth Foundation responded: "It is a pleasure to cooperate with AFR100. We have sponsored more than 150 local projects." Meta did not respond to media inquiries.
Editor's Note
[1] The word Restoreation has two meanings: "restoration" and "restoration". The definition of "restoration" in traditional ecology is strict, and "planting trees" on farmland cannot be called "restoration." However, the scope of the AFR100 plan is broader, including agroforestry, afforestation, restoration, assisted natural succession, etc. Therefore it is translated as "restoration".
References:
*AFR100 official website
*The Guardian (2024/02/15), Ill-judged tree planting in Africa threatens ecosystems, scientists warn
*Science (2024/02/15), Conflation of retrostation with restoration is widespread
*The Verge (2024/02/16), A Big Tech-backed campaign to plant trees might have taken a wrong turn
* Deutsche Welle (2021/03/25), When planting trees does more harm than good
*University of Liverpool (2024/02/15), 'Misguided' reforestation programs could threaten vast areas of tropical grasslands
Source: Environmental Information Center
