Young forests regrowing on lands where mature forests once stood could hold the key to removing billions of tons of carbon dioxide, which in turn could accelerate much-needed action on climate change. That is according to a study, Protect young secondary forests for optimum carbon removal, revealing that 20- to 40-year-old forests (on average) sequester the optimal amount of carbon, eight times more than newly regenerating forests.
Led by Professor Adriane Esquivel-Muelbert and Dr. Tom Pugh, both from the University of Birmingham, global scientists reported that if 800 million hectares of restorable forests began regenerating this year, up to 20.3 billion metric tons of carbon could be removed over the next 25 years. And while carbon removals vary across biomes and ecoregions, with tropical forests reaching their peak in carbon removal capacity much quicker than boreal or Mediterranean forests, they argue that policymakers can no longer afford to delay forest regeneration.
“Our research underscores the critical role young secondary forests play in the global fight against climate change. The upcoming COP30 in Belém presents a critical opportunity for world leaders to take decisive action,” Esquivel-Muelbert said. “We urge policymakers to prioritise protection and regeneration of young secondary forests as a key component of climate mitigation strategies…this can help us achieve faster and more substantial carbon removal, contributing to climate goals.”
Using a dataset of more than 100,000 field estimates, Esquivel-Muelbert and Pugh’s team employed advanced random forest models to predict carbon densities in five-year age intervals, from five to 100 years, resulting in detailed global maps of carbon removal rates: “Current carbon market methodologies often overlook the protection of very young secondary forests. This study highlights the need to revise these methodologies to credit the substantial carbon removal potential of these forests,” Pugh said.
For more information: Nathaniel Robinson et al, Protect young secondary forests for optimum carbon removal, Nature Climate Change (2025). DOI: 10.1038/s41558-025-02355-5.
