Phenological pattern and community structure of dipterocarpaceae in Bukit Barisan Selatan National Park, Lampung

Most of the tropical lowland dipterocarp forests in Indonesia have been fragmented and isolated due to excessive logging and forest fire. In addition, the growth of dipterocarp is generally slow. If these conditions persist, it will eventually decrease the dipterocarp’s population. Information on phenological patterns and community structure are one of the basic pieces of knowledge for conservation management. We conducted research to answer these questions: what was the phenological pattern and population dynamics of Dipterocarpaceae, and to what extent did phenological pattern affect population dynamics of Dipterocarpaceae? We found that the dipterocarps in Bukit Barisan National Parks show sub-annual flowering seasons, in which flowering occurs more than one cycle per year. It is different from the common dipterocarps’ phenological pattern that usually has super-annual pattern or mass flowering. The pattern of the flowering and fruiting season in dipterocarp phenology begins with the emergence of new leaves in March, flowering in April, and ends with the appearance of the fruit in May or 3-5 months later. There are 11 dipterocarps species in the study area; 3 of them are critically endangered, 2 are endangered, 1 is vulnerable, and the others are not listed in the IUCN Red List. Dipterocarps’ populations were dominated by Vaticaobovata, Dipterocarpushumeratus, and D. haseltii. However, even though mass flowering and fruiting season are believed to represent an evolutionary adaptation of flowering and fruiting patterns in plants to face high mortality, the phenological pattern does not seem to have affected the population dynamics of dipterocarps.