[A-CG33_28PO1] Environmental changes in the Japanese Alps region

[ACG33-P03] Spatial and temporal changes in soil respiration in an old-growth forest on the slope of Mt Hakusan

*Toshiyuki OHTSUKA¹, Vilanee SUCHEWABORIPONT¹, Yasuo IIMURA², Shinpei YOSHITAKE¹ (1.Gifu University, River basin research center, 2.University of Shiga Prefecture, School of Environmental Science)

Keywords:Soil respiration, cool-temperate region, old-growth forests, carbon cycling, beech forests

Structure and function of cool-temperate beech forests have been dramatically altered by disturbance. Especially in old-growth forests, canopy disturbance has important influences on the structure and organization of forest communities. As a result, the complexity of forest structure affects the spatial difference in micro-environmental factors such as soil temperature and soil water content. Therefore, the spatial and temporal changes in soil respiration were studied using soda lime in 1-ha study site, and automated open-close chamber using IRGA (AOCC method) in canopy and gap areas in 2013 in an old-growth beech forest, Mt Hakusan. The spatial pattern with the different vegetation and micro-environmental factors showed the high efflux in canopy and the low efflux in gap. All soil effluxes increased from spring (Jun.-Jul.) to summer (Aug.), and then decreased in autumn (Sep.-Nov.). The seasonal pattern showed the hysteresis loop that soil respiration in spring was greater than that at the same temperature in autumn. Diel soil efflux was greatly controlled by soil temperature but a diel lag between soil respiration and soil temperature led to diurnal hysteresis loop in some season.