[A-CG40] Material Circulations in Land Ecosystems

[ACG40-02] Influence of tree- thinning on long-term CO₂ exchange over a larch forest

*Yoshiyuki Takahashi¹, Nobuko Saigusa¹, Ryuichi Hirata¹, Naishen Liang¹, Reiko Ide¹, Munemasa Teramoto¹ (1.Center for Global Environmental Research, National Institute for Environmental Studies)

Keywords:CO2, flux, disturbance, long-term observation

Larch forest is an important research object for evaluating CO₂ uptake by forests because it is a common tree type of plantation that has been planted widespread over northeastern Japan. Quantifying the influence of the forest management on carbon budget in larch forests have significance on the securement of forests as a source of CO₂ absorption. Thus, National Institute for Environmental Studies (NIES) has implemented long-term monitoring program of CO₂ exchange over larch forests. Fuji Hokuroku Flux Observation Site was established in the foothills of Mt. Fuji as an alternative base for monitoring, and began observations in January 2006. The site is dominated by larch trees of more than 50 year-old. 30% thinning was conducted at the site in spring of year 2014 and 2015. The characteristics of CO₂ exchange were affected from the human disturbance. Gross primary production (GPP) and ecosystem respiration (RE) of CO₂ were remarkably decreased temporarily after the thinning. Consequently, both GPP and RE has recovered gradually. Net ecosystem production (NEP) has not fully recovered at 2017 to the level before the thinning because the speed of the recovery differs for GPP and RE. We will introduce the results of carbon fluxes and related parameters for the sites.