Heat-Treated Wood from Grand Fir Provides the Same Quality Compared to Silver Fir

Abstract

Grand fir (Abies grandis/Dougl. ex D. Don/Lindl.) represents the North American species that has the potential to replace and complement to some extent several commercial European species, in particular, Norway spruce and silver fir. This is not only due to its high production potential but also because of its favorable effect on the soil compared to spruce or pine. We tested sample trees from these tree species growing in the same location for physical and mechanical wood properties and evaluated the effect of the thermal treatment (180 °C and 200 °C) on their wood. Wood density, swelling, surface properties, strength, and stiffness were the properties used to find the differences among species. Grand fir obtained higher values for density and compressive strength compared to silver fir. For the remaining properties, these tree species are comparable, except for toughness, which was significantly lower for grand fir. Grand fir wood was even comparable with Norway spruce in the case of density and compressive strength. The thermal treatment resulted in a decrease in density, swelling, wettability, modulus of rupture, and toughness while increasing compressive strength. The effect of the thermal treatment was similar for all tested species. From this perspective, grand fir represents a potential substitute for the timber of endangered European commercial conifers.