Gross primary production and net ecosystem exchange of a cool-temperate deciduous forest estimated by the eddy covariance method

摘要

Broadleaf deciduous forest is one of the major vegetative constituents of the main island of Japan. Natural ecosystem dominated by oak (Quercus mongolia) is widespread not only in Japan, but also in Korean Peninsula, northeastern China, and eastern Mongolia. Recent studies have shown that there is a strong relationship between CO_2 uptake of forests and meteorological conditions such as solar radiation and air temperature. Yamamoto et al. (1999) reported that the annual net CO_2 uptake of a broadleaf deciduous forest in Japan has year-to-year variability in correlation with the variations of the solar radiation and summer air temperature. Using a regional scale climate model with biological land surface processes, Mabuchi et al. (2000) suggested that the inter-annual variation of the solar radiation is mainly responsible for the inter-annual variation of the net CO_2 flux over the Islands of Japan, The purposes of this study are to (1) conduct the flux measurements of heat, water vapor, and CO_2 by the eddy covariance method over a major ecosystem in Japan, (2) estimate the sensitivity of the carbon budget of the ecosystem to climatic conditions.