Tropical forests are often converted  for agricultural land use, but have the ability to regrow naturally on abandoned fields through secondary succession. This symposium advances successional theory by addressing the drivers and mechanisms of secondary forest succession, and by taking a hierarchical approach, scaling up from individuals to communities and ecosystem functioning. It provides generalization by using case studies from three continents and through pantropical synthesises. We use the obtained insights on secondary succession to provide recommendations for passive and active forest restoration to green up the world.