Characterization of growth and wood properties for three Populus species naturally grown in Mongolia

To support sustainable forestry and the wood industry in Mongolia, the growth and wood properties (oven-dry density, modulus of elasticity [MOE], modulus of rupture [MOR], and compressive strength parallel to the grain) were investigated for three Populus species, Populus laurifolia, Populus suaveolens, and Populus × sibirica, growing in Mongolia. The average annual growth rate was highest for P. × sibirica (0.37 cm y−1), followed by P. suaveolens (0.25 cm y−1), and P. laurifolia (0.14 cm y−1). The measured wood properties—oven-dry density, MOE, MOR, and compressive strength—were 0.43 g cm−3, 6.63 GPa, 54.4 MPa, and 31.8 MPa for P. laurifolia; 0.43 g cm−3, 5.71 GPa, 53.7 MPa, and 28.7 MPa for P. suaveolens; and 0.47 g cm−3, 6.91 GPa, 72.9 MPa, and 33.3 MPa for P. × sibirica. The mechanical properties tended to be higher in P. × sibirica, although only MOR showed a significant interspecific difference. In addition, regarding radial variation of wood, while the oven-dry density remained nearly constant from the pith to the bark side, the MOE and MOR were low around the pith side, increased sharply, and then remained nearly constant. Compressive strength increased from the pith to the bark side. A correlation analysis between growth rate and wood properties revealed that growth rate does not negatively affect wood properties. It was also found that wood density is a good indicator for estimating mechanical properties.