| CH4 and N2O fluxes from soils under tropical seasonal rain forest and rubber (Hevea brasiliensis) plantation in Xishuangbanna, SW China, were measured by using closed static chamber and gas chromatography method. Three treatments were set in the studied rain forest field: (A) litter-free, (B) with litter, and (C) with litter and seedling. Factors such as plant and management style were discussed in the study for rubber plantation. The results showed:1) The soil under rain forest was the sink of CH4. The soil under rubber plantation was the sink of CH4 and consumed less CH4 than rain forest. The soils under rain forest and rubber plantation were the source of N2O.2) There were seasonal variations in CH4 and N2O for the two forest soils. Litter decreased CH4 uptake of the rain forest soil by 28.2 and 25.1% in 2003 and 2005, respectively. Seedling increased N2O production of the rain forest soil by 62.5%. The plant and management style did not influence CH4 flux, and the plant style did not influence N2O flux for rubber plantation soil, but fertilization significantly increased N2O production.3) Calculated annual CH4 fluxes were -4.1, -3.1, -2.9 kg C hm-2 for treatments A,B,C in 2003, respectively, and -3.58, -2.92 kg C hm-2 for treatments A,B in 2005, respectively. Calculated annual N2O fluxes were 2.8, 2.6, 3.7 kg N hm-2 for treatments A,B,C in 2003, respectively, and 1.62, 1.60 kg N hm-2 for treatments A,B in 2005, respectively. The soil under rubber plantation consumed CH4 (1.7 kg C hm-2 ) and produced N2O (14.4 kg N hm-2).Using an infra-red gas analyzer (IRGA) method, we measured stem respiration for 11 predominant species of tropical rain forest and rubber trees at 4 ages. The results were:1) The mean stem respiration rates for 11 dominant species of tropical rain forest ranged from 0.823 to 2.727μmol m-2 s-1, and for 4 ages rubber trees ranged from 2.299 to...
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