Abstract: The relationship between soil seed bank and aboveground vegetation in several tropical forests of Xishuangbanna was studied by experimental method. The results show that at the initial succession stage of forest, there were more species of soil seed bank common with its aboveground vegetation and their seed storage, but the proportion of seeds from exotic species was gradually increased with increased forest age. The seeds in soil seed bank at mature forest stage were mostly from pioneering species outside of the communities, which would hardly germinate under closed canopy. But, when forest gaps or opens occured after the forests disturbed, these seeds would germinate rapidly, and play an important role in vegetation restoration or succession.

Key words: Secondary succession, Soil seed bank, Tropical forest, open-path infrared gas analyzer, fine-wire thermocouple, Burba correction, surface heating effect, optical path temperature