Lowland tropical forests cycle large quantities of silicon (Si) via litterfall, but little is known how litterfall Si flux is modified in logged forests. In Sabah, Borneo, we compared an old-growth forest stand and stands that had received reduced-impact logging (RIL) or conventional logging (CL) about 20-30 years ago, in terms of Si concentration of recently abscised dead leaves, Si flux via litterfall, and water extractable Si from upper soil horizons. The Si concentration of dead leaves produced by dominant tree species in Dipterocarpaceae differed widely among genera and species (1.2-29.7 mg Si g-dry-mass À1 ). Some pioneer trees (e.g., Macaranga spp.) and bamboo species that dominate the RIL and CL stands exhibited high Si concentration in their dead leaves. Litterfall Si flux was higher in the RIL stand (392 kg ha À1 year À1 ) where bamboo was abundant, than in the CL and old-growth stands (187 and 153 kg ha À1 year À1 , respectively). Water extractable Si from the soil was also