Natural forest regrowth found up to 96% cheaper than planting for climate and biodiversity goals

Research from the University of Queensland and the University of Newcastle has found that natural forest regeneration in the tropics can achieve substantial carbon sequestration and biodiversity gains for up to 96% less cost than traditional tree-planting efforts. The study, published in Nature Ecology & Evolution, mapped how the costs and ecological benefits of natural regrowth vary across tropical regions.

Lead author Jiaqi Li, a Ph.D. candidate at the University of Queensland, explained that tree planting requires purchasing seeds and hiring labor for planting and ongoing management. In contrast, natural regeneration mainly requires removing invasive species, ensuring adequate seed sources are present, and protecting the area from fire, grazing, and human disturbance, after which the process becomes largely self-sustaining.

The researchers identified "holistic hotspots" where natural regeneration offers high carbon benefits, high biodiversity benefits, and low restoration costs simultaneously. These areas are concentrated in Indonesia, Madagascar, the Philippines, Mexico, and Malaysia. Carbon benefits are most pronounced in Neotropical regions such as the Amazon basin and in Indomalayan areas including Borneo, Sumatra, and Papua New Guinea, while biodiversity benefits are greatest in the Afrotropics, particularly Madagascar.

Between 2000 and 2012, tropical forests declined by 2.3 million square kilometers, releasing an estimated 0.86 gigatons of carbon annually and affecting roughly 1.5 billion people who depend on forests. Tropical forests cover 18% of global land area but harbor more than half of all terrestrial vertebrate species, making their restoration critical for both climate and biodiversity targets.

Senior author Dr. Brooke Williams of the University of Newcastle noted that the 2022 Kunming-Montreal Global Biodiversity Framework commits nations to restoring 30% of degraded land, a goal that may be financially out of reach if reliant solely on active planting. The study provides a broad framework for estimating the benefits and costs of natural regeneration to help countries prioritize investments.

Co-author Associate Professor Matthew Luskin said the research translates theoretical understanding of forest restoration into practical guidance. The findings are intended to help countries and communities decide where and how to allocate restoration resources based on their specific goals and budgets.