Burnt wood management enhances soil multifunctionality at the medium term after a large wildfire in north-west Spain

Abstract

Background Mulching and burnt wood treatments are commonly applied to prevent the loss of soil quality and erosion, but their effect on soil multifunctionality remains unexplored. Aims We filled this gap by assessing the medium-term (4 years) effects of these treatments on soil multifunctionality after a large wildfire in NW Spain. Methods Straw mulching (SM) and cut plus lopping (CpL) treatments were applied in high-severity affected areas of heathland plant communities. CpL areas had been afforested with Scots pine 15 years before the fire. We considered four soil functions estimated in treated and burned control plots 4 years after fire: (1) carbon regulation; (2) water regulation; (3) soil fertility; and (4) nutrient cycling. The functions were integrated into a multifunctionality index and linear models were used to evaluate treatments effect. Key results SM had no impact on individual functions and multifunctionality. Conversely, CpL with burnt Scots pine wood was able to sustain higher levels of multiple functions simultaneously than control areas. Consistent trade-offs between soil functions emerged in control areas for both treatments. Conclusions Burnt wood could ensure long-lasting effects to promote soil multifunctionality in Mediterranean ecosystems. Implications We recommend using a multifunctionality approach to avoid biases in treatment success.