Effects of steaming treatment on the technological properties of olive wood

Abstract

Wood modification is a process that alters the properties of wood through chemical, thermal, or physical treatments, thereby improving its performance, including durability and dimensional stability. Steaming is a hygrothermal treatment that can modify physical properties and may affect mechanical performance depending on process severity. This study investigated the effects of low-temperature steaming on olive wood (Olea europaea L.) by applying a constant temperature (80 °C) and varying treatment duration (12, 18, and 36 h) compared with natural seasoning (control). Color and dynamic modulus of elasticity (MOE_d) were measured on boards before and after treatment; after, specimens were tested for dimensional stability, bending properties (MOR and MOE_s), compression strength, Janka hardness, and abrasion resistance. Steaming produced significant color changes in both heartwood and sapwood, with stronger responses in sapwood. Bending properties showed non-significant increasing trends, with mean MOR increasing from 50.21 MPa (control) to 62.24–64.71 MPa and the highest mean MOE_s observed in the 12 h group (+ 13.45% vs. control). Compression strength was comparable to the control (56.34–57.77 MPa). Janka hardness showed a decreasing tendency (up to − 21.3% in the 12 h group), while abrasion weight loss increased slightly and differed significantly among groups (0.21% in control vs. 0.24–0.29% after steaming). Overall, low-temperature steaming at 80 °C appears suitable for improving olive wood color uniformity and selected technological performance while limiting the mechanical degradation typically associated with high-temperature thermal modification.