Annual variation of carbon flux and impact factors in the tropical seasonal rain forest of xishuangbanna, SW China

摘要: Two years of eddy covariance measurements above-and below-canopy carbon fluxes and static opaque chamber gas chromatography technique soil respiration for three treatments (bare soil, soil+litterfall, soil+litterfall+seedling) were carried out in a tropical seasonal rain forest. In addition, data photosynthesis dominant tree species seedlings, leaf area index, litter production decomposing speed, moisture, temperature photosynthetic photon flux density within the forest all measured concurrently. Data from January 2003 to December 2004 are used present annual variability relationships between impact factors. The results show that this presented unusual tendency variation; above-canopy negative dry season (November–April) mainly positive rainy season, but overall is sink. Carbon has obviously diurnal variation Above-canopy day-time absolute values larger than causing act as sink; at night, positive, source. Dominant have greater capability which great effect on flux. There was significant correlation rate species. also seedlings; however, only significantly correlated with seedlings during hot-dry season. Soil displayed markedly dynamic; well respiration, litterfall pro-duction, decomposition rate, precipitation, moisture temperature. A primary sta-tistical result study showed source or sink effects different seasons, it scale year.