Mast seeding following general flowering is a unique phenomenon in Southeast Asia. The purpose of this study is to describe and analyze the long-term patterns of growth and reproduction of tree species in lowland and hill dipterocarp forests. We established the two sets of 100 seed traps at 2-ha core areas in the 6-ha permanent plots in Pasoh (lowland) and Semangkok (hill) Forest Reserve, Peninsular Malaysia. Monthly litter data from 1993 to 2016 showed the supra annual complex patterns of leaf and seed litter production. Tree biomass and vegetative growth were stable against rainfall fluctuation. On the other hand, seed production largely affected by soil drought under low rainfall, particularly in January to March. Recent studies emphasize that these drought is a major trigger for general flowering. The mast-seeding year was coincided in the two dipterocarp forests on 1996, 2002, 2005, and 2014. These mast seeding have a possibility to decrease the percentage of seed predation and immature seeds. Flowerings were occurred after droughts but severe droughts in 2010 and 2015 in Pasoh did not induce general flowering. The threshold of soil water contents for flowering may change by year and differ between each dipterocarp forests.