Tropical forests play a crucial role in the global carbon cycle. Biosphere-atmosphere exchange of carbon is controlled by nutrient cycles via their impact on forest growth and dynamics. The African continent holds the second largest continuous block of tropical forest worldwide, and is subjected to an increasing human pressure via shifting agriculture, resulting in increasing deforestation rates. This study aims at understanding the biogeochemical interactions along tropical regrowth trajectories. The study will focus on how land-use history and atmospheric phosphorus (P) input control the biogeochemical and ecological recovery of African regrowth forests. The biogeochemical knowledge of regrowing tropical forests is currently limited to either ‘snapshots’ or longer-term monitoring of C cycling only. This study wants to merge longer-term monitoring efforts on N and C cycling with the P-cycle along well-documented sites in the central Congo basin, and will result in the first study that integrates C-N-P cycling along regrowth trajectories in the Congo Basin. This is important for a future where secondary forests are becoming more abundant than primary forests in the tropics.