Selected physical and mechanical properties and circular reuse potential of driftwood and fire-affected wood in Mediterranean ecosystems

Wildfires and extreme hydrological events in Mediterranean regions generate significant quantities of environmentally exposed wood biomass that is often classified as waste due to presumed structural degradation. However, quantitative evidence regarding its retained mechanical performance remains limited. This study presents a comparative evaluation of marine and riverine driftwood and fire-affected wood collected in southern Croatia. Seven Mediterranean wood species were identified and tested under controlled laboratory conditions. Physical properties (moisture content, density, porosity) and mechanical properties (compressive strength parallel to the grain, bending strength, and modulus of elasticity in bending) were determined. The results show that poplar, hackberry, cypress, oak, pine, and olive retained 75–100% of reference mechanical properties (compressive strength, bending strength, and modulus of elasticity), suggesting potential suitability for controlled non-structural applications. Strength reductions were primarily associated with biological defects and grain deviations, resulting in increased variability rather than uniform degradation. Wood that retains a substantial portion of its reference mechanical properties may be considered suitable for controlled non-structural and value-added applications, although further validation is required. These findings indicate the potential for incorporating environmentally exposed wood into the circular bioeconomy systems and highlight opportunities for improved resource efficiency in Mediterranean ecosystems.