L. M. Curran, ^12* I. Caniago, ³ G. D. Paoli, ¹ D. Astianti, ⁴ M. Kusneti, ⁵ M. Leighton, ⁶ C. E. Nirarita, ⁷ H. Haeruman ⁸

Dipterocarpaceae, the dominant family of Bornean canopy trees, display the unusual reproductive strategy of strict interspecific mast-fruiting. During 1986-99, more than 50 dipterocarp species dispersed seed only within a 1- to 2-month period every 3 to 4 years during El Niño-Southern Oscillation events. Synchronous seed production occurred across extensive areas and was essential for satiating seed predators. Logging of dipterocarps reduced the extent and intensity of these reproductive episodes and exacerbated local El Niño conditions. Viable seed and seedling establishment have declined as a result of climate, logging, and predators. Since 1991, dipterocarps have experienced recruitment failure within a national park, now surrounded by logged forest.

¹ Department of Biology and
² School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109, USA.
³ U.S. Agency for International Development-Natural Resource Management, Pontianak, West Kalimantan 78121, Indonesia.
⁴ Department of Forestry, University of Tanjungpura, Pontianak, West Kalimantan 78121, Indonesia.
⁵ World Wide Fund for Nature, WWF-Indonesia, Samarinda, East Kalimantan 75117, Indonesia.
⁶ Department of Anthropology, Harvard University, Cambridge, MA 02138, USA.
⁷ Wetlands International-Indonesia, Bogor, Java 16002, Indonesia.
⁸ National Development Planning Agency, Jakarta, Java 10310, Indonesia.
^*   To whom correspondence should be addressed. E-mail: lcurran{at}umich.edu