Characteristics of CO_2 release from forest soil in the mountains near Beijing

摘要

CO_2 release from forest soil is a key driver of carbon cycling between the soil and atmosphere ecosystem. The rate of CO_2 released from soil was measured in three forest stands (in the mountainous region near Beijing, China) by the alkaline absorption method from 2004 to 2006. The rate of CO_2 released did not differ among the three stands. The CO2 release rate ranged from -341 to 1,193 mg m~(-3) h~(-1), and the mean value over all three forests and sampling times was 286 mg m~(-2) h~(-1). CO_2 release was positively correlated with soil water content and the soil temperature. Diurnally, CO2_ release was higher in the day than at night. Seasonally, CO_2 release was highest in early autumn and lowest in winter; in winter, negative values of CO_2 release suggested that CO_2 was absorbed by soil.