CO2 efflux from leaf litter focused on spatial and temporal heterogeneity of moisture

Leaf litter respiration (R _LL) was directly measured in situ to evaluate relationships with the water content in leaf litter (WC), which is distributed heterogeneously under natural conditions. To do so, we developed a small, closed static chamber system using an infrared gas analyzer, which can measure instantaneous R _LL. This study focuses on the measurement of CO₂ effluxes from leaf litter using the chamber system in the field and examines the relationship between R _LL and WC among seven broadleaf species in a temperate forest. The measurements focused on the position of leaves within the litter layer, finding that both R _LL and WC were significantly higher in the lower layer. The value of R _LL increased with increasing WC, and the response of R _LL to WC was similar among all seven species. Moreover, the temporal variation in WC differed among three species and was associated with leaf litter thickness. The observed heterogeneity in WC induced by the physical environment (e.g., position and thickness of leaf litter) affects the variation in WC and, therefore, both R _LL and the decomposition rates of organic matter in the litter layer.