Effects of light-felling on non-growing season greenhouse gas emission from soils in Korean pine forests in Maoer Mountains, China.

Abstract

Non-growing season soil greenhouse gas emission may play an important role in the forest ecosystem carbon and nitrogen cycle. However, it is not clear about the effects of the cutting distur-bance on soil greenhouse gas emissions during non-growing season. The CO2, CH4 and N2O fluxes and related environmental factors (soil temperature, water content, carbon and nitrogen, etc.) were monitored in the Korean pine plantation (fifty year-old) under different light-felling manners (control, no cutting; the half light-felling, cutting 50% of broad-leaved trees in canopy; the whole light-felling, cutting 100% of broad-leaved trees in canopy), using static chamber technique and gas chromatography during non-growing season in Maoer Mountains of China. The main aim was to reveal the influence of cutting disturbance on soil greenhouse gases emission during non-growing season and its controlling factors. The results showed that the whole and half light-felling manners significantly decreased CO2emission flux by 21.0% and 22.8%, and N2O by 23.5% and 11.2%, and decreased CH4uptake by 16.0% and 16.4%. The contribution of non-growing season CO2, CH4 and N2O emission to annual total was 11.7%-14.2%, 13.1%-17.0% and 63.9%-72.6%, respectively. Light-felling manners decreased annual cumulative contribution of CO2 by 1.4%-2.5%, that of CH4 by 0.7%-3.9%, but increased that of N2O by 2.4%-8.7%. Furthermore, light-felling increased the correlations of soil CO2 fluxes with soil temperature, soil water content, nitrate and ammonium, and decreased its correlation with soil organic carbon content. Light-felling increased the correlations of soil CH4 flux with soil water content, soil pH, soil organic carbon, ammonium, and decreased its correlation with nitrate. Light-felling increased the correlations between soil N2O flux and soil temperature, decreased the correlations with nitrate and ammonium, and changed the positive correlation with soil pH to negative. Therefore, light-felling had significant effects on the emission fluxes of the greenhouse gas during non-growing season, with the whole light-felling decreased more soil N2O emission flux than the half light-felling.