New Maps Show Best Places for Global Reforestation: Study

Researchers have revealed new maps that show the best places to regrow forests across the world to tackle the climate crisis.

The areas include western Canada, the eastern United States, Colombia, Brazil and Europe. They add up to a total of 482 million acres that, if reforested, would remove 2.43 million tons of carbon dioxide each year — nearly as much as all the total carbon emissions produced by the European Union, reported The Guardian.

“Natural climate solutions (NCS) are ecosystem stewardship actions that protect, manage, and restore natural and working lands to provide measurable climate change mitigation, and have garnered increasing international and policy recognition,” the authors of the study wrote. “Reforestation — the restoration of forest cover via tree planting, direct seeding, or natural regrowth in places where forests are absent but naturally occur — is especially promising because it is the largest and most cost-effective option for carbon removal.”

New maps show reforesting areas across the globe could remove 1.5bn tonnes of CO2 a year without harming people or wildlife. Reforestation opportunity maps like this are essential as regrowing trees remains a cost-effective option for removing CO2 from the atmosphere. Graphic: @theguardian.com

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— Atmos (@atmosmag.bsky.social) June 11, 2025 at 2:37 PM

The research team that developed the new maps considered earlier maps that had suggested regrowing trees was possible in larger areas, but took a more conservative approach, focusing on regions with the most potential and least number of issues.

The team focused exclusively on dense forests with closed canopies, excluding areas that had recently been impacted by wildfires.

The 482 million acres that could potentially be reforested is an area 90 percent smaller than had been shown on previous maps. The researchers took into consideration the importance of avoiding social conflicts with Indigenous Peoples, which is critical, since nearly 100 million people live within the prospective replanting area.

Maps that show opportunities for reforestation are important since tree planting is the biggest and least expensive carbon removal option. However, it’s important for these initiatives to focus on areas that are most suitable for regrowing trees in order to maximize their impact.

“Reforestation is not a substitute for cutting fossil fuel emissions, but even if we were to drive down emissions tomorrow, we still need to remove excess CO2 from the atmosphere,” said senior author of the study Dr. Susan Cook-Patton, lead reforestation scientist with The Nature Conservancy’s Natural Climate Solutions team, as The Guardian reported. “Many, many years of evolution have gone into trees figuring out how to suck CO2 from the atmosphere and lock it into carbon stores, so it’s ready to scale now.”

Cook-Patton said that, as the world’s climate-fueled disasters increase, there is no time to waste on “hazily-understood interventions.”

“We must fast-track our focus toward the places with greatest benefits for people and nature and the fewest downsides, the places most likely to be win-win. This study will help leaders and investors do just that,” Cook-Patton said.

The scientists who created the map prioritized three criteria: improving water quality and biodiversity; avoiding social conflicts; and highlighting areas where reforestation goals had already been established by governments, which makes action more politically realistic.

The land area that met all the criteria was small, and the researchers hope NGOs and governments will use their maps to pinpoint the best solutions in their countries.

Excellent coverage of our new paper in Nature Communications in the Guardian. Will post a thread later, but this is a great summary: www.theguardian.com/environment/…

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— Forrest Fleischman (@forrestf.bsky.social) June 11, 2025 at 7:18 AM

“Previous studies often failed to address how reforestation could have negative effects on human well-being, especially for poor people living in the remote rural areas often targeted for reforestation,” said study co-author Dr. Forrest Fleischman, an associate professor of environmental and natural resource policy at the University of Minnesota. “These negative effects are more likely when people lack secure land rights, are highly dependent on natural resources for food and fuel, and live in countries where political rights are not respected.”

While removing these places from the map reduced the potential reforestation areas by roughly a third, the remaining lands would still be able to remove approximately 1.65 billion tons of carbon each year. These regions were mostly focused in Canada, the U.S., Australia, Europe and Brazil.

“Who wants to see the natural grasslands like the Serengeti covered in trees and not lions, elephants and other wildlife? And planting trees in places that burn isn’t going to store carbon long-term, and so of course these areas should be excluded,” Lewis said. “The most conservative map removes potential forest restoration across almost all of Africa and Southeast Asia, due to fears of [land rights] conflict. This risks perpetuating poverty, if investments in nature avoid poor countries with limited governance. Plans to invest in nature to improve local livelihoods and also benefit the climate and biodiversity should be seized, as these often go hand-in-hand.”