Coarse woody debris reduces the rate of moisture loss from surface soils of cleared temperate Australian woodlands

Abstract

Reintroductions of coarse woody debris (CWD) to Australia’s temperate woodlands have been proposed to offset the impacts of long-term tree removal. However, the magnitude of the reduction in the rate of surface-soil moisture loss due to CWD is not known. Gravimetric soil moisture content was measured at different distances from CWD for 12 samples in a cleared temperate woodland. Sampling was conducted at regular intervals following a major rain event in late summer. Lower soil bulk densities near CWD indicated higher levels of soil carbon. A multivariate nonlinear statistical model was constructed to explain the observed soil moisture content as a function of time after rainfall, distance from CWD and CWD diameter. The model demonstrated that rates of soil moisture loss increased with increasing distance from CWD. Drying times near CWD were 40% longer than drying times at reference distances from CWD. The model also showed that CWD diameter influenced the rate of soil moisture loss, with larger diameters yielding reductions in soil moisture loss over greater distances from CWD. Locations of greater soil moisture availability associated with CWD may be particularly advantageous for organisms sensitive to low soil moisture levels and may increase productivity, particularly in water-limited ecosystems.