An area of forest the size of France has regrown naturally across the world in the last 20 years, a study suggests. The restored forests have the potential to soak up the equivalent of 5.9 gigatonnes (Gt) of carbon dioxide — more than the annual emissions of the US, according to conservation groups. A team led by WWF used satellite data to build a map of regenerated forests. Forest regeneration involves restoring natural woodland through little or no intervention. This ranges from doing nothing at all to planting native trees, fencing off livestock or removing invasive plants. William Baldwin-Cantello of WWF said natural forest regeneration is often “cheaper, richer in carbon and better for biodiversity than actively planted forests”.