Abstract: Forest is an important pool of carbon in the terrestrial ecosystem.Stem respiration is an important part of the carbon balance in the forest stands.The objective of our research is to address the following questions:The daily and seasonal variation of the stem respiration rates,and the relationship between stem respiration rates and the impact factors in a montane evergreen broad-leaved forest.In this study, infrared gas analyzer (IRGA) method was applied to measure the stem respiration by connecting LI-840 CO2 gas analyzer to a custom-built Polyvinyl Chloride (PVC) chamber,the stem respiration rates of three dominant tree species in a montane evergreen broad-leaved forest were measured from February,2009 to January,2010.The daily variation of Machilus bombycina and Schima noronhae was measured in the dry and wet season.The results demonstrated that the stem respiration rate of the tested tree species had an obvious seasonal variation,with the maximum occurred in September.The fluctuation of daily variation of the stem respiration rate,stem temperature and air temperature was not significant.The response of stem respiration to temperature differed among tree species and diameter classes. There was significant correlation between stem respiration and DBH (R2=0.216).