Effects of thermal modification on the water resistance and colour stability of wood species from Bosnia and Herzegovina

Redžo Hasanagić; Selma  Mujanić; Mohsen Bahmani; Miha Humar

doi:10.26614/les-wood.2025.v74n01a02

Authors

Redžo Hasanagić
Selma Mujanić
Mohsen Bahmani
Miha Humar

DOI:

https://doi.org/10.26614/les-wood.2025.v74n01a02

Keywords:

thermal modification, sorption, water resistance, colour change, indigenous wood species

Abstract

This study investigates the impact of thermal modification on the water resistance and colour stability of Indigenous wood species from Bosnia and Herzegovina, including Norway spruce (Picea abies), silver fir (Abies alba), oak (Quercus sp.), and walnut (Juglans regia). Thermal modification, conducted in the presence of air, enhanced the hydrophobicity of all tested wood species by reducing their water absorption and limiting their susceptibility to moisture-driven dimensional changes. The modification process also induced notable colour changes, darkening each species in line with the degradation of lignin and other wood constituents. The degree of colour change was observed to increase with higher treatment temperatures, particularly at 210 °C, as measured by the CIE Lab colour system. These findings suggest that thermal modification provides an environmentally friendly method to improve both durability and aesthetic appeal in wood, extending the material’s application range for humid or outdoor environments.

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