CO 2 flux in a cool-temperate deciduous forest (Quercus mongolica) of Mt. Nam in Seoul, Korea

The Namsan Ecological Tower Site based on a flux tower was equipped with eddy covariance and automatic opening/closing chamber systems to collect long-term continuous measurements of flux, such as the net ecosystem exchange (NEE) and soil efflux in a cool-temperate Quercus mongolica forest. The mean concentrations of atmospheric () during the summer were smaller than those measured () during the winter. The mean flux during the summer period was negative (), while that during the winter period was positive (). was deposited from the atmosphere to the surface in the summer. The daily mean value of soil efflux increased from spring to summer. The seasonal pattern in the rate of soil efflux tightly followed the seasonal pattern in soil temperatures. The values for soil efflux varied in a range from 2.12 to 3.26, and increased with increasing soil depth. The maximum value of total carbon uptake (i.e., NEE) during the growing season was . At the same time, the rate of soil efflux was . The amplitude of flux variations in NEE was approximately 14% larger than those in soil efflux. These results suggest that in cool-temperate regions of the Korean peninsula, the forest ecosystem of Q. mongolica may have a larger atmospheric uptake, due primarily to its high photosynthetic capacity and low ecosystem respiration.