Soil CO2 efflux in a beech forest: comparison of two closed dynamic systems

摘要: The aim of this study was to understand why two closed dynamic systems with a very similar design gave large differences in soil CO2 efflux measurements (PP and LI-COR). Both the field (forest beech stand) laboratory, PPsystems higher estimations than LI-COR system (ranging from 30% 50%). difference wind speed occurring within respiration chambers (0.9 m s−1 SRC-1 0.4 LI-6000-09 chambers) may account for discrepancy between systems. An excessive air movement inside chamber is thought disrupt high laminar boundary layer over forest floor. This would promote an exhaust accumulated into upper layers lateral diffusion towards chamber. reduced (i) by decreasing fan SRC-1, (ii) increasing surface outside chamber, or (iii) using artificial without concentration pores. We show that important component which must be taken when measuring efflux, even on fine textured like silt-loam soil. Proper measurement can achieved maintaining below since low conditions predominate under canopies. However, more accurate will obtained regulating speeds at velocity representative recorded simultaneously floor surface.