Speaker
Description
Shifting cultivation and wood extraction have given rise to a vast expansion of secondary forests - i.e. regrowing forests on clearcuts or fallow land – across the wet tropics. These disturbances do not just remove biomass—they transfer nutrients in space and time, with potential implications for the regrowth of secondary forests. Ash pulses, biomass export, leaching, and lateral transport move nutrients from vegetation to soil and then out of the landscape. We argue that these transfers might lead to landscape-scale nutrient depletion, which in turn might govern the speed of secondary forest regrowth. We identify nutrient cations (Ca, Mg, K) as being particularly vulnerable on the old, highly weathered soils that are characteristic for the majority of lowland tropical forests.
We present emerging evidence from both observations and experiments in central Africa: (1) along succession, available phosphorus is being cycled in excess, while exchangeable base cation availability was found to decline; (2) cations increasingly accumulate in woody biomass through time, making them susceptible to permanent loss when wood is removed; (3) In a pot experiment, tree growth responded first to cation additions (and secondarily to N), indicating that cations potentially directly limit productivity.
Together, these results highlight a landscape-level problem: disturbance-driven nutrient transfers deplete the “cation capital” needed for resilient recovery. We outline how ongoing work couples field budgets, tissue stoichiometry, and targeted fertilization experiments to parameterize a biogeochemical model, enabling scenario tests of how management can conserve nutrients and sustain carbon uptake in regenerating tropical forests.
| If your abstract is not accepted for an oral presentation, would you be interested in presenting it as a poster instead? | Yes |
|---|---|
| If accepted by the Scientific Board, I agree to have my presentation/poster and abstract published on the Belgian Climate Centre websites and social media. | Yes |
