Diurnal pattern of soil CO2 efflux in a pinus densiflora forest measured using an open-flow chamber system

Abstract

This study was conducted to investigate the diurnal pattern of soil CO2 efflux (RS) using an open-flow, closed-chamber system for a 70- to 80-year-old Pinus densiflora forest in the Gwangneung Experimental Forest in central Korea. The daily mean RS rate (g CO2 m-2 h-1) was 0.486 in September, 0.073 in April, and 0.169 in May 2010. Although RS exhibited a diurnal pattern that was similar to the soil temperature pattern, the pattern varied seasonally. The Q10 value was 4.57 and 4.26 for day and night time, respectively. The annual RS rate was estimated as 6.16 t C ha-1 y-1 by the relationships between RS and soil temperature using continuous measurements, but as 6.73 t C ha-1 y-1 by using the 11:00 h mid-morning point measurements. Our study results demonstrate the necessity of measuring the diurnal pattern of RS throughout the whole year in order to obtain an accurate estimate of annual RS using an open-flow, closed-chamber system. © 2010 Taylor & Francis Group, LLC.