Poorly planned tree planting harms essential ecosystems

92% of all new tree plantations established in the tropics between 2000 and 2012 were in the wrong places, have a negative impact on fragile biodiversity and little chance of success.

As research and our understanding of the climate crisis grows and improves, so does the seeming complexity of the problem. Now, a study of the effects of tree planting to improve the planet’s carbon sequestration and storage capabilities offers alarming evidence that many such projects have been poorly designed and poorly executed.

In terms of numbers, the University of Maryland Baltimore County (UMBC) assessment suggests that 92% of all new tree plantings established in the tropics between 2000 and 2012 were in hotspots of the biodiversity, with 14% in arid biodomes where tree species are unlikely to thrive but extremely likely to damage existing ecosystems.

Many have also encroached on protected national parks, with 9% of the conversational landmass in the humid tropics now affected in this way. Given that 45% of reforestation commitments under the Bonn Challenge take the form of tree planting, understanding the overall impact is critical to ensuring a safe and effective response to the climate crisis.

“Environmentalists have been sounding the alarm about this for more than a decade, but no one has a hard figure on the scale of what is actually happening.” said Matthew Fagan, assistant professor of geography and environmental systems at UMBC, citing projects in China where trees have been planted at the edge of the Gobi Desert and in Egypt where plantations are found at the intersection between dunes Saharan and Sahelian grasslands. In both cases, the soil disturbance released carbon, with the overall effect of “killing the grasslands that were there”, while the trees often die of drought.

“In the United States, we have a large area of ​​relatively wet woods, and we tend to idolize tree planting as some sort of ultimate environmental act,” Fagan continued. “But there’s a lot of value in grasslands and savannahs that we don’t necessarily see. And when you plant trees, you basically destroy that ecosystem…I would really like to see governments around the world reevaluate their restoration plans, or at least be more transparent when their plans involve planting trees, especially in areas which may not be suitable for planting. trees.’

Despite these concerns, a 2019 study by Ohio State University concluded that plants and trees offer the cheapest and most effective way to remove air pollution, supporting the idea that the way and location of planting projects are key to their success.

Image credit: Etienne Boulanger