[Effects of harvest on greenhouse gas emissions from forested swamp during non-growing season in Xiaoxing'an Mountains of China.]Ying Yong Sheng Tai Xue Bao 2019; 30(5):1713-1725YY
Soil greenhouse gas emission during non-growing season plays an important role in ecosystem carbon and nitrogen cycling in mid and high latitude regions. However, the effects of harvest on greenhouse gas emission during non-growing remain unclear. We measured the fluxes of CO2, CH4 and N2O and environmental factors (soil temperature, moisture, soil organic carbon and total nitrogen etc.) during non-growing season from four kinds of forested swamps (Alnus sibirica swamp, Betula platyphylla swamp, Larix gmelinii-Carex schmidti swamp, L. gmelinii-moss swamp) under different harvest disturbances for 10 years, including control (no cutting), 45% selective cutting, clear cutting, by using static chamber technique and gas chromatography in Xiaoxing'an Mountains, Northeast China. The aim of this study was to reveal the effects of harvest on greenhouse gas emission from temperate forested swamp during non-growing season and the main controlling factors. The results showed that the average fluxes of CO2, CH4 and N2O from four kinds of swamps distributed in 53.08-81.31 mg·m-2·h-1, 0.09-3.07 mg·m-2·h-1 and 4.07-8.83 μg·m-2·h-1, respectively. Clear cutting significantly increased the fluxes of CO2, CH4, and N2O from A. sibirica swamp and L. gmelinii-moss swamp. Selective cutting significantly increased CO2 fluxes from B. platyphylla swamp and L. gmelinii-moss swamp and decreased CO2 flux from A. sibirica swamp. Selective cutting significantly decreased CH4 fluxes from all the four forested swamps and N2O flux from Larix gmelinii-Carex schmidti swamp. The CO2 fluxes from natural forested swamps were strongly influenced by soil temperature, soil organic carbon and C/N. CH4 fluxes were influenced by soil temperature, soil organic carbon. N2O fluxes were affected by air temperature and soil pH. Harvesting increased the correlation between soil CO2 flux and air temperature, soil moisture and snow depth, the correlation between soil CH4 flux and air temperature, soil moisture and C/N, as well as the correlation between soil N2O flux and soil total nitrogen and C/N. The annual cumulative contribution of CO2, CH4 and N2O emission from natural forested swamp during non-growing season were 33.2%-46.5%, 6.3%-9.1% and 61.5%-68.3%, respectively. The clear cutting increased the annual cumulative contribution of CO2 from B. platyphylla swamp and L. gmelinii-moss swamp and that of N2O from other swamps except L. gmelinii-moss swamp. The selective cutting increased the annual cumulative contribution of CO2, CH4 and N2O from L. gmelinii-C. schmidti swamp and L. gmelinii-moss swamp, but decreased that from B. platyphylla swamp. The annual cumulative contributions of N2O and CO2 during non-growing season were relatively high from temperate natural forested swamps, and clear cutting further increased their contribution, while the selective cutting just increased that of CH4 during non-growing season.