The family Dipterocarpaceae includes 470 tree species from 13 genera in South and South-East Asian tropical forests (Ashton 1982). Many dipterocarp species in aseasonal lowland rain forests of western Malesia flower synchronously during masting (or general flowering) events, which usually occur at irregular intervals of 2–10 y (Ashton et al. 1988). Very few individuals flower at other times, and successful recruitment of seedlings is limited to those masting events (Ashton et al. 1988, Curran et al. 1999).