Summary:
Allowing degraded tropical forests to recover with limited human assistance may offer a lower-cost route to rebuilding ecosystems while supporting climate and biodiversity goals. Researchers from The University of Queensland and the University of Newcastle assessed restoration costs and ecological benefits across 7.49 million km² of tropical land with biophysical potential for natural forest regeneration.
The new study published in Nature Ecology & Evolution estimates that if all of this land regenerated, the resulting forests could accumulate about 9.57 gigatonnes of carbon over 30 years and reduce extinction risk across forest-dependent species by around 31% compared with the study baseline. The analysis also identified places where low restoration costs coincide with strong carbon and biodiversity benefits.
Indonesia, Madagascar, the Philippines, Mexico and Malaysia contained the largest areas of these combined-benefit zones. However, locations that performed well for carbon alone or biodiversity alone often differed, leaving only 9.67% of the study region classified as these “holistic hotspots.” The researchers say the maps could help decision-makers target restoration investment according to ecological priorities and available resources.
— Press Release —
Natural restoration is key to reviving threatened tropical rainforests
A study from The University of Queensland and the University of Newcastle found natural forest regeneration delivered substantial carbon and biodiversity benefits and could be up to 96 per cent cheaper than traditional tree-planting programs.
School of the Environment PhD candidate Jiaqi Li said the team researched how the costs and benefits of natural regeneration varied across the tropics and created an interactive global map to explore the opportunities for forest regions.
“Nature is a great gardener, sometimes we just need to get out of its way while providing a bit of support,” Ms Li said. “For tree planting you need to purchase the seeds and hire workers or recruit volunteers to plant and manage them, which is costly. For natural regeneration people just need to check the land for invasive species and remove them, check there is adequate seed sources, put up protection from fire, grazing animals, and humans and then it is mostly self-sufficient. For many cases of natural regeneration, studies show that you can end up with a forest that could store more carbon and is more biodiverse than a planted forest.”
It’s been calculated that between 2000 and 2012, tropical forests were reduced globally by 2.3 million km², leading to the release of an estimated 0.86 gigatons of carbon annually and threatening the well-being of around 1.5 billion people dependent on forest.
Read also: Why tropical trees cool more and burn less than forests elsewhere
“Forests are Earth’s life support systems and tropical forests are the most biodiverse amongst all the forest types, covering 18 per cent of the land and home to more than half of all land vertebrate species,” Ms Li said. “They are also a giant carbon sink, so when deforestation happens we not only stop the forest up taking the carbon, but we also flip it and turn it into a carbon source.”
Ms Li said the study identified areas where natural regeneration provided high carbon benefits, high biodiversity benefits and low restoration costs and called them ‘holistic hotspots’.
These areas were mostly located Indonesia, Madagascar, Philippines, México, and Malaysia.
“The carbon benefits stand out most in Neotropic areas like the Amazon basin and in the Indomalaya Tropics like Borneo, Sumatra and Papua New Guinea,” Ms Li said.
“There are more biodiversity benefits in the Afrotropic including Madagascar.”
Senior author Dr Brooke Williams from the University of Newcastle said with the world pledging in 2022’s Kunming-Montreal Global Biodiversity Framework to restore 30 per cent of the Earth’s degraded land, natural restoration was more important than ever.
“The whole world is fighting to combat climate change and on top of that nations have goals to reverse the biodiversity crisis,” Dr Williams said.
“Restoring forests is expensive and the cost could mean some nations can’t meet their ambitious restoration goals. Our study gives a broad idea of the benefits and costs which could occur with natural regeneration.”
UQ Associate Professor Matthew Luskin who co-authored the study said the research was a huge leap forward in putting theories about forest restoration into practice.
“I’ve spent years in the forests around the tropics and seen rampant deforestation first-hand, but I’ve also seen huge opportunities for regrowth,” Dr Luskin said. “This work will help countries and communities prioritise where and how to invest in restoration depending on their specific goals and resources to achieve the best outcomes.”
Journal Reference:
Li, J., Luskin, M.S., Chazdon, R.L. et al., ‘Variation in the costs and ecological benefits of tropical natural forest regeneration’, Nature Ecology & Evolution (2026). DOI: 10.1038/s41559-026-03154-7
Article Source:
Press Release/Material by The University of Queensland
Featured image credit: David Clode | Unsplash
