Conservative species drive biomass productivity in tropical dry forests

1. Forests account for a substantial part of the terrestrial biomass storage and productivity. To better understand forest productivity we need to disentangle the processes underlying net biomass change. 2. We tested how above-ground net biomass change and its underlying biomass dynamics (biomass recruitment, growth, and mortality) can be explained by four alterative and contested hypotheses; the soil fertility, biomass ratio, niche complementarity and vegetation quantity hypotheses. 3. Above-ground biomass dynamics were evaluated over a five-year period in 200 permanent sample plots in 8 tropical dry forests in Brazil, and related to soil fertility, community-weighted mean (CWM) traits that are important for carbon storage and sequestration (wood density, specific leaf area, maximum stem diameter and deciduousness), species richness, functional diversity, and initial stand biomass. 4. Initial stand biomass was the best predictor of all three processes of biomass dynamics, providing str...