| Wetlands are important sources and sinks of greenhouse gases, natural wetlands are seriously damaged result from the human activities are growing intensively. The wetlands are always in XiaoXing'an Mountainns, DaXing'an Mountainns and ChangBai Mountainns in our country. Firing is one of the importance disturbances in XiaoXing'an Mountainns Which is one of forest in our country. The change of greenhouse gases emission from our wetlands is result from the frost is disturbed by firing fact. A static chamber and gas chromatography were employed to investigate the effects of low-and high-intensity burning on CH4, CO2 and N2O discharge by larch swamp of the three kinds of Larix gmelinii wetland, which are follows: Larix gmelinii-Carex schmidtii, Larix gmelinii-moss, and Larix gmelinii-Sphagnum spp.The results show that:In Larix gmelinii-Carex schmidtii wetland, fire disturbance increased CO2 fluxes by 24.0-45.9% and increased CH4 fluxes by 135.1% in the case of light burning and decreased CH4 fluxes by 31.3% in the case of heavy burning, and shifted the burning site from a N2O sink to a N2O source. Severe fire disturbance greatly affected the seasonal dynamics of CO2 fluxes, and the fire intensity affected seasonal variations in CH4 and N2O fluxes. CO2 emissions at the study sites had significant negative correlation with the water level, and the temperature had significant positive correlation with the soil temperature. CH4 emissions from the site at which there was low-intensity burning had significant negative correlation with the level of the water table and significant positive correlation with the soil temperature at 0 cm. The flux of CH4 emissions from the site with low-intensity burning had positive correlation with air temperature and some individual soil temperatures, whereas that from the site with high-intensity burning and the flux of N2O emissions from sites with low-intensity, high-intensity and no burning had no relationship with soil temperature or the level of the water table. The CO2 emission intensity at burning sites and CH4 emitted from the lightly burning site were both higher than respective values for the site where there was no burning, but the CH4 emission intensity from the heavily burning site was less than that at the site where there was no burning. Fire disturbance converted a site from a weak sink of N2O into a weak source. The global warming potential of the fire-disturbance sites increased by 1/4-1/2 relative to that of the site with no burning, with the potential increasing with the increasing intensity of the fire disturbance.In Larix gmelinii-moss wetland, fire disturbance decreased CO2 fluxes by 27.1% and Fire disturbance converted CH4 fluxes of this site from a weak sink of CH4 into a weak source and converted N2O fluxes of this site too. Light fire disturbance didn't greatly affect the seasonal dynamics of CO2 fluxes, which is the same to the site where there was no burning is summer>spring>august, and the fire intensity affected seasonal variations in CH4 and N2O fluxes. In this kind of wetland,CH4 fluxes from spring and summer sinking,august emission to all the growing season emission and which is summer>august>spring; N2O fluxes from spring sinking and summer, august emission to spring, summer emission and august sinking to the site which is no burning. CO2 emissions at the study sites had significant negative correlation with the water level, and the temperature had significant positive correlation with the soil temperature. CH4 emissions from the site at which there was low-intensity burning had significant negative correlation with the level of the water table and significant positive correlation with the soil temperature at 0-20cm. the flux of N2O emissions from sites with low-intensity had no correlation with the water level and the temperature. The global warming potential of the fire-disturbance sites decreased by 1/5 relative to that of the site with no burning, with the potential increasing with the importance intensity of the CO2 fluxes.In Larix gmelinii-Sphagnum spp wetland, fire disturbance increased CO2 fluxes by 63.7% and Fire disturbance decreased CH4 fluxes by 4.1% in the case of light burning and decreased N2O fluxes by 67.3% and shifted the burning site from a CH4 and N2O source to a weak source. The site of fire and no burning, CO2 emission is the same that is summer>august>spring. Light firing converted CH4 and N2O emission from sink in spring, source in summer and fall to sink in spring, source in summer, fall and emission in all the growing season. CO2 emissions at the study sites had significant negative correlation with the water level, and the temperature had significant positive correlation with the soil temperature. CH4 emissions from the site at which there was low-intensity burning had significant negative correlation with the level of the water table and significant positive correlation with the soil temperature at 0-15cm. the flux of N2O emissions from sites with low-intensity had negative correlation with the water level and positive correlation with the temperature which is 5-15cm and 40cm. The GWP of the fire-disturbance site increased by 3/5 relative to the site where there was no firing.On the whole, in the Global Warming Potential composition, the dominant position is CO2 fluxes, CH4 and N2O fluxes proportion of less than 9%, which is a very secondary position.
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