Achieving cost-effective landscape-scale forest restoration through targeted natural regeneration

High costs of tree planting are a barrier to meeting global forest restoration targets. Natural forest regeneration is more cost-effective than tree planting, but its potential to foster restoration at scale is poorly understood. We predict, map, and quantify natural regeneration potential within 75.5\ua0M ha of deforested lands in the Brazilian Atlantic Forest. Of 34.1\ua0M ha (26.4%) of current forest cover, 2.7\ua0M ha (8.0%) regenerated naturally from 1996 to 2015. We estimate that another 2.8\ua0M ha could naturally regenerate by 2035, and a further 18.8\ua0M ha could be restored using assisted regeneration methods, thereby reducing implementation costs by US$ 90.6 billion (77%) compared to tree planting. These restored forests could sequester 2.3 GtCO of carbon, reduce the mean number of expected species at risk of extinction by 63.4, and reduce fragmentation by 44% compared to current levels. Natural regeneration planning is key for achieving cost-effective large-scale restoration