Abstract: A monthly measurement of soil CH₄ uptake rate (V_CH4) in a natural Castanopsis carlesii forest in Wanmulin Natural Reserve of Fujian Province, East China was conducted from March 2010 to February 2011. The V_CH4 showed a pronounced seasonal fluctuation, being higher in summer-autumn than in winter-spring, with the maximum value (95.13 μg·m^-2·h^-1) in September and the minimum value (9.13μg·m^-2·h^-1) in March. With the increase of soil temperature and moisture, the V_CH4 showed an increasing and a decreasing trend, respectively, but the correlations of the V_CH4 with soil temperature and moisture were not significant. The annual soil CH₄ flux of the forest (3.93 kg·hm^-2·a^-1) was higher than the average value of global natural forests (2.4 kg·hm^-2·a^-1) and of Asian tropical natural forests (2.07 kg·hm^-2·a^-1), but lower than that of Asian temperate natural forests (8.12 kg·hm^-2·a^-1).

Key words: mid-subtropics, natural Castanopsis carlesii forest, CH₄ uptake rate, soil temperature, soil moisture