Seasonal and topographic patterns of forest floor CO₂ efflux from an upland oak forest

Forest floor CO₂ efflux (FF_cer) is an important component of global carbon budgets. FF_cer exhibited a distinct seasonal trend following patterns of soil temperature, but soil water content and the volume percent of the soil's coarse fraction were also correlated with observed rates. Over the entire measurement period, FF_cer ranged from a typical minimum of 0.8 μmol m^-2 s^-1 to an average maximum near 5.7 μmol m^-2 s^-1. No significant differences in FF_cer were observed among the ridge-top and slope positions, but FF_cer in the valley-bottom locations was lower on several occasions. An empirical model of FF_cer based on these observations is suggested for application to whole-stand estimates of forest carbon sequestration. -from Authors