Automated closed-chamber measurements of methane fluxes from intact leaves and trunk of Japanese cypress

摘要

Continuous in situ measurements of methane (CH_4) fluxes from intact leaves and trunk of Japanese cypress (Chamaecyparis obtusa Sieb. et Zucc) were conducted in a temperate forest from August 2009 to August 2010. An automated closed-chamber system, which was used to evaluate CO_2 exchange between the atmosphere and forest ecosystems, was coupled to a laser-based instrument to monitor CH_4 concentrations. Temporal changes in CH_4 concentrations from the foliage and trunk were measured at one-second intervals during chamber closure to determine CH_4 fluxes between the leaf and trunk surfaces and the atmosphere. While recent studies have suggested that some plants emit CH_4 under aerobic conditions, emission or uptake of CH_4 in detectable amounts with our experimental system, by intact leaves or the trunk of C obtusa, was not significantly observed throughout the measurement period.