The research team also surveyed timber concessions throughout the surrounding province of West Kalimantan and studied 30 years of export records to determine the impact of logging in the region and on the park. Curran's study is the first to document an ecosystem with a rare reproductive strategy called masting. Curran discovered that these bursts of reproduction are initiated by the arrival of the El Nino Southern Oscillation or ENSO, a periodic shift in tropical Pacific circulation patterns that brings drought to Indonesia. According to Curran, masting gives canopy trees an important survival advantage. Wild boar, orangutans, parakeets, jungle fowl, partridges, and other animals congregate to stuff themselves.
Local villagers collect baskets of seeds called illipe nuts to sell as a cash crop.
Because so much seed is produced simultaneously over such a large area, however, there is still enough leftover to germinate and produce a carpet of new seedlings on the forest floor. In the Science article, Curran and her co-researchers describe how the forest in Gunung Palung is changing following a decade of intensive dipterocarp logging in huge timber concessions surrounding the park. Despite a major fruiting event during the 1998 El Nino year, no new dipterocarp seedlings were found in the survey area. Because seed predators can't find food outside the park, they move inside to eat the dipterocarp seeds before they germinate, according to Curran. Massive forest fires on nearby logging plantations, which destroyed an area the size or Denmark or Costa Rica in 1997-98, brought pollution and intensified El Nino's drought killing the few remaining dipterocarp seedlings.