Seed production and dispersal of four Lauraceae species in a tropical lower montane forest, Northern Thailand

Seed production and dispersal of two pioneer species (Litsea cubeba and Lindera metcalfiana) and two shade-tolerant species ( Cinnamomum soegengii and Cryptocarya densiflora) of Lauraceae were studied at a tropical lower montane forest in Doi Inthanon National Park, northern Thailand. Mature seed fall was monitored weekly to monthly using seed traps or belt transects for 1-3 trees per species. During the two-year study period (1998-2000), we observed only one fruiting episode for each of ten sample trees. Fruiting period was synchronized within each species, while there was no overlap in fruiting among the species. The seed fall periods were relatively short in Litsea cubeba (16-54 days), Lindera metcalfiana (25-65 days) and Cinnamomum soegengii ( 69 days), while quite long in Cryptocarya densiflora (159-187 days). The seed dispersal distance was short for all the species ( less than 12 m), and the density of seed dispersal had a mode at 0-2 m from mother tree. The total seed production of each tree was estimated by a Weibull seed dispersal model as 93-6029, 985-3977, 1035-8910 and 6331 for Lindera metcalfiana, Litsea cubeba, Cryptocarya densiflora and Cinnamomum soegengii, respectively. Total fruit dry weight of each tree was estimated to be comparable to the leaf dry weight for the shade-tolerant species, while less than 3% of the leaf dry weight for the pioneer species. The studied method should be applied for other species in order to gain more ecological knowledge to maintain the montane forest.