Letting Nature Lead the Way
As nations race to restore ecosystems and curb climate change, research has shown that letting nature do the work is a cost-effective and viable solution. A study from the University of Queensland and the University of Newcastle found that natural forest regeneration delivered substantial carbon and biodiversity benefits and could be up to 96 per cent cheaper than traditional tree-planting programs. The research was published in the journal Nature Ecology & Evolution.
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 seeds and hire workers or recruit volunteers to plant and manage them, which is costly," she explained. "For natural regeneration, people just need to check the land for invasive species and remove them, make sure there are adequate seed sources, provide protection from fire, grazing animals and humans, and then it is mostly self-sufficient."
Ms Li added that in many cases, natural regeneration can result in a forest that stores more carbon and is more biodiverse than a planted forest.
The Scale of the Challenge
Between 2000 and 2012, tropical forests were reduced globally by 2.3 million km² (890,000 square miles), 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 forests.
"Forests are Earth's life-support systems, and tropical forests are the most biodiverse among all forest types, covering 18% 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 from taking up carbon, but we also flip it and turn it into a carbon source."
Identifying Priority Areas
The study identified "holistic hotspots" where natural regeneration provided high carbon benefits, high biodiversity benefits, and low restoration costs, mostly located in Indonesia, Madagascar, the Philippines, Mexico, and Malaysia. Carbon benefits were found to be strongest in Neotropical areas like the Amazon basin and in the Indomalayan tropics like Borneo, Sumatra, and Papua New Guinea. Biodiversity benefits were strongest in the Afrotropics, including Madagascar.
Dr. Brooke Williams from the University of Newcastle highlighted the financial pressures that restoration goals can create: "Restoring forests is expensive and the cost could mean some nations can't meet their ambitious restoration goals."
Matthew Luskin from the University of Queensland also commented, drawing on his field experience: "I've spent years in forests around the tropics and seen rampant deforestation firsthand, but I've also seen huge opportunities for regrowth."
A Global Commitment
The research comes as the world has pledged, under the 2022 Kunming-Montreal Global Biodiversity Framework, to restore 30% of Earth's degraded land. The study's interactive global map is intended to help governments and conservation groups identify where natural regeneration is most likely to succeed, providing a practical tool to support these ambitious targets.