Planting a tree in the Amazon does a lot less for the rainforest than simply leaving one alone. That’s the uncomfortable arithmetic in new research on Brazil’s jungles.
Faced with a dollar to spend on the rainforest, scientists found, you’re almost always better off protecting what’s already standing than paying to regrow what’s gone. The gap isn’t small: preventing deforestation or stopping logging and fires delivered far more carbon storage and biodiversity than restoration did, for a fraction of the cost, according to new research in Science.
And while efforts to save rainforests often focus on halting the conversion to open land, it turns out squelching logging and fires could bring even more benefits for biodiversity.
“Protection must go beyond avoiding deforestation,” said Leonardo Miranda, the study’s lead author and a biodiversity researcher at the United Kingdom’s Lancaster University. “Avoiding forest disturbances from wildfires or logging delivered the greatest benefits for forest biodiversity.”
The insights are based on the fate of more than 3 million hectares of land across Santarém and Paragominas, areas in northern Brazil, between 2010 and 2020. Using satellite images to track the condition of the forests there down to the level roughly a square kilometer, the scientists found that during the decade, nearly 160,000 hectares were entirely deforested, 273,000 were either burned or logged, and almost 130,000 hectares regrew into forest.
What would have happened to the carbon and wildlife on that land if policies had prevented all deforestation, or all logging and wildfires, or if reforestation had sped up to hit established government targets? To compare those scenarios, the scientists built computer models showing alternate versions of the jungle in 2020. They then used detailed measurements of wildlife and carbon taken in 2010 at 381 locations scattered across the jungle to estimate how these different “2020” worlds would have affected biodiversity and carbon storage.
The results showed the biggest benefits came from avoiding deforestation (61% more carbon and 24% more biodiversity compared to the real 2020) or preventing logging and fires (47% for carbon and 69% more biodiversity). Both far outranked the benefits of the newly regrown forest (15% more carbon and 7% more biodiversity).
The differences between deforestation and what the scientists called more subtle “disturbance” probably come down to the different dynamics influencing carbon and wildlife, and what patches of land were affected by each kind of forest damage. Full deforestation can wipe out much more of the carbon stored in trees and the forest floor, but it tends to occur at the edges of places that have already been cleared. Those areas already have less wildlife in them, so saving that land came with fewer biodiversity benefits, the scientists concluded. By contrast, even disturbed forest held onto more carbon. But wildfires and logging tended to hit more remote, intact forests filled with more wildlife.
Still, to increase both carbon and wildlife levels in the jungle it takes more than one strategy, the scientists found. “Net-gains in biodiversity and carbon storage were only achieved” when both deforestation and disturbance were halted, said Miranda. “Combined interventions will be even more important as climate change progresses, especially as forest restoration can be particularly vulnerable to wildfires.”
In addition to being more effective, preventing forest loss is also cheaper. The researchers calculated the cost of each strategy, both in terms of money spent and lost opportunities, such as earnings from crops grown on former forests. For every Brazilian real (the country’s currency) it cost, the biodiversity and carbon benefits of regrowing forest were a tiny fraction of the gains from protecting existing forests.
In other words, it might be politically easier to replant abandoned pastures than to tell large companies and land speculators they can’t touch the forest, or to establish new fire-fighting programs. But economically and environmentally, it’s foolhardy.
“Investing in new forests makes little sense if, at the same time, we fail to protect existing forests,” said Joice Ferreira, a co-author and scientist at Embrapa, a Brazilian research organization. “Otherwise, we are pouring money into a leaky pot.”
Miranda, et. al. “Protecting tropical forests is more cost-effective for biodiversity and climate than restoration.” Science. Sept. 17, 2026.
Image: ©Anthropocene Magazine
