Natural forest regeneration is a low-cost and efficient alternative for active reforestation efforts and is often the only possibility for ecosystem restoration in low-income countries. The global area of these naturally regenerating forests has already surpassed that of primary forests and will keep increasing because of the ever-growing anthropogenic pressures. These secondary forests are especially prominent in Central Africa, a region where smallholder slash-and-burn agriculture is by far the prevalent method of food and energy production. Despite their large extent, the recovery trajectories of these regrowth forests are still poorly confined. To create a comprehensive view of the ecological and biogeochemical recovery of these secondary forests, my Ph.D. contains various work packages related to the recovery of soil nutrient cycling, the effects of increased land-use intensity on secondary forest dynamics and agricultural yields, and the recovery of aboveground carbon stocks and biodiversity on the African continent. Characterizing forest regrowth in Africa will fill important knowledge gaps, with clear management implications and improvement of integrated assessment models. The latter is particularly critical since global change models are biased by the lack of data from the Congo Basin, the second-largest tropical forest on Earth. Finally, the urgency of studying secondary forests is reflected in the UN’s decision to declare 2021-2030 the ‘Decade on Ecosystem Restoration’, with the characterization of natural forest regrowth being critical to identify focus areas for ecosystem restoration.