Efflux of CO2 from soil in Norway spruce stands of different ages: a case study

Efflux of CO2 from soil is a major component of the terrestrial ecosystem and plays an important role in the global carbon cycle. In this study the efflux of CO2 from soil was measured in three stands of Norway spruce. We investigated differences in the efflux of CO2 from soil in different age classes of the forest: two young (YR and YBK) and one old (OR) stand, during the growing season in 2010. The lowest amount of soil CO2 released was recorded in OR (14.9 t ha−1), which was just over half that recorded in the young stands. There were no significant differences in total soil CO2 released recorded in YR and YBK (29.3 and 27.2 t ha−1). Efflux of CO2 recorded in OR and YR during July was low because of lack of rain. When the efflux of CO2 from soil in OR and YR, respectively, was estimated on the basis of the soil moisture measured at YBK, the modelled cumulative amount of soil CO2 released increased by 10.9 and 11.4%. Our results indicate that the age of a stand can be an important and easily obtained factor for predicting the amount of soil CO2 released at the regional level.