General flowering in lowland mixed dipterocarp forests of south-east Asia

The general flowering (GF) events of forests in south-east Asia are perhaps the most spectacular phenomena in tropical biology. GF events occur at multiyear intervals. In GF, most dipterocarp species and many plants of other families come into flower and set fruit massively; these species and plants rarely flower except during GF events. GF is unique, because it can occur over thousands of kilometers and involve hundreds of plant species representing diverse families and lifeforms. It also involves strict mast fruiting. Satiation of generalist seed predators has been considered a primary force for GF. However, recent observations indicate that several selective agents rather than a single major factor may shape GF. In addition to the satiation of generalist predators, promotion of pollination could be one of the selective factors for GF, since synchronized flowering of many species causes an increase in pollinator activity through immigration and population growth. Although environmental prediction for better establishment of seedlings may also be involved in GF, no field data have been reported to support this idea. Long-term monitoring and further understanding of GF are essential for the conservation of this unique and diverse tropical forest in south-east Asia, especially in a period of global climatic change.