PATTERNS OF FLOWERING AND SEED PRODUCTION IN EUCALYPTUS-MINIATA AND E-TETRODONTA IN A TROPICAL SAVANNA WOODLAND, NORTHERN AUSTRALIA

The reproductive phenology-the annual and spatial variation in tree fe cundity, ovule development and seedfall-of Eucalyptus miniata Cunn. ex Schauer and E. tetrodonta F. Muell. is described at a tropical savann a site in northern Australia from 1992 to 1994. There was substantial inter-annual variability in fecundity of both species at the individua l and the population level. The proportion of ovules which survived di d not vary significantly between years. Seed production and seedfall v aried substantially between years with large seed yields in 1994 and l ow seed yields in 1993. Eucalyptus miniata and E. tetrodonta are separ ated in time (by 2-8 weeks) with respect to peak periods for all key p henology events-budding, flowering and seedfall. Both species are non- serotinous with all seed shed within 8 months of ovule initiation. Pea k seedfall occurred up to 1 month before the first wet season rains fo r E. miniata and coincided with these rains for E. tetrodonta. Post-di spersal conditions for germination and establishment are more likely t han seed supply to limit seedling establishment of E. miniata and E. t etrodonta.