Mechanical Properties of Grand Fir Wood Grown in the Czech Republic in Vertical and Horizontal Positions

Abstract

Strength properties were evaluated for Grand fir wood (Abies grandis /Douglas/ Lindl.), a North American species that is considered to be a promising species for the Central European forestry industry. The bending, compression, and impact strengths of wood from Grand fir trees grown in the Czech Republic area were tested, including their variability within a stem and correlation to wood density. The average values of the compression strength reached 39.577 MPa; the bending strength was 78.119 MPa, the impact strength was 4.186 J/cm2, and the density was 410.267 kg/m3. The greatest dependence of the strength characteristics on the evaluated density was shown in the case of bending at the vertical bottom position (r = 0.95). Compression strength values were observed to highly correlate with the density at vertical positions (bottom and middle) in the first site (r = 0.98). The values of the correlations between density and impact strength were observed to be moderate or poor in the vertical position, where a good value was shown in the middle position (r = 0.87). The results of the study suggest that Grand fir is a satisfactory substitute for indigenous species of fir in the Czech Republic; with respect to bending strength and toughness, it can replace the most important commercial conifer, spruce.