The study shows that the natural growth of tropical forests has enormous potential to solve environmental problems

A: study in Nature finds that up to 215 million hectares of land (an area larger than Mexico) in the humid tropics worldwide has natural growth potential.

That much forest can store 23.4 gigatons of carbon over 30 years, as well as having a significant impact on concerns such as biodiversity loss and water quality. The study found that more than half of the area with strong growth potential is located in five countries: Brazil, Mexico, Indonesia, China and Colombia.

“Planting trees in degraded landscapes can be expensive. By using natural restoration methods, nations can effectively achieve restoration goals,” said study co-author Brooke Williams, a researcher at Queensland University of Technology in Australia. Environmental Decision Capacity Exchange Institute.

“Our model can guide where to best take advantage of those savings,” he says.

The culmination of decades of work

Matthew Fagan, associate professor of geography and environmental systems at the University of Maryland, Baltimore County (UMBC) and second author of the new study, developed the data set on which the authors relied.

In that job“We used it satellite images identify millions of small areas where tree cover has increased over time. We then excluded areas planted by humans with machine learning, focusing on natural growth,” says Fagan.

The study tracked the increase in growth between 2000 and 2012, and then tested whether the growth was sustained through 2015. “Those natural patches were the input to this new study,” he says, “the first to predict where future forest growth will occur, taking into account: there was an increase in the past.”

The research, led by Hawthorne Beyer, head of geospatial science at Brazilian startup Mombak, which aims to generate high-quality carbon credits through Amazon forest restoration, and science director of the Environmental Decision Capacity Exchange Institute. in global data sets that describe factors such as land quality, slope, road and population density, local wealth, distance from urban centers and healthy forests, and more.

“Any time you build one of these global studies, you’re standing on the back of a lot of other scientists,” Fagan says. “Each of these studies represents years of work.”

The study found that the factors most associated with high growth potential were proximity to existing forest, density of nearby forest, and soil carbon content. Those factors in particular “seem to do a really good job of explaining the patterns of regrowth that we’re seeing around the world,” Fagan says.

Fagan explains that proximity to an existing forest, for example, is important for supplying the area with a range of seeds to support diverse growth.

Keep local by providing a global map

The end result of the research is a digital map of the global tropics, where each pixel representing a 30 x 30 square meter plot of land shows potential for regrowth. Made possible by an extensive international collaboration of researchers, the map is a boon to conservationists around the world who hope to advocate for their efforts at the local level.

“Our goal and hope is that this will be used democratically by local people, organizations and communities, from the county level to the national level, to advocate for where recovery needs to happen,” Fagan says.

“The people living there should be responsible for what happens there. where and how to recover really depends on local conditions.”

Fagan notes that some of the potential restoration areas identified by the study are unlikely to be restored for a variety of reasons, such as being actively used for ranching or cropping, or being on prime real estate near roads and urban centers.

However, much of the 215 million hectares are abandoned and degraded cattle pastures or previously logged forests, where encouraging natural regeneration would have minimal costs to local economies and a long list of benefits.

“If you were to restore that in the rainforest, the benefit to water quality, water security, local biodiversity and soil quality would be enormous,” Fagan says.

“It would also be a huge benefit for removing carbon from the atmosphere, so it’s really just a question of: “Where can we do this most effectively?” That’s what this paper is about.”