Dynamics of soil seed bank and seedlings in Fushan broadleaf forest

The components and density in the soil seed bank, and seedlings emergence and survival rate at 2 sites in the Fushan hardwoo forest were examined for 1 cyear. On 2 sites, the litter layer andd 0-5 cm soil layer of 20 X 20 cm plots were used to estimate the species and density (ind./m2) of seed content, while 0.5 X 2 m plots werecused to monitor seedling emergence and survival rate. Four censuses in the year indicated that the main components of the soil seed bank were understory shade -tolerant tree species, e.g. Eurya acuminata var. acuminata(33%), melastromataceae species (28%), and herb.(26%). seeds of pioneer tree species could be found at 0-5 cm soildepth in every sampling plot. The seeds of canopy species were mostly found at the surface of theforest floor, but a amount was very scarce. The understory seedling eurvival rate was pretty low, and varied from Engelhadtsia roxboughiana (10%), Myrica rubra(24%), Machilus thunbergii (29%) to Machilus zuihoensis(41%). However, in forest gap and edge, seedling survivl rate was high (above 80%) for all species found. This result indicates that E. roxbouhina and N.rubra may be gap species. The seed distribution pattern of Lauraceae species was mostly aggregated. No germinable Fagaceae seeds were found in the study area. The species composition of the upper canopy, which was dominated mainly by Fagaceae tree species, was quite different from that of the soil seed bank. The seedling survival rate of Lauraceae tree species was severly restrained by ground cover and litterfall. I general, the seedling bank, instead of the seed bank, would be the major source for recuriment of upper canopy species in the forest.