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.