© 2019, The Author(s). Annual ring width, warp, dynamic Young’s modulus, and static bending properties were evaluated for 2 × 4 lumber produced from Larix sibirica trees naturally grown in five different provenances of Mongolia. The lumber was also visually graded according to Japanese Agriculture Standard for structural lumber for wood frame construction. Mean values of dynamic Young’s modulus, modulus of elasticity, and modulus of rupture for lumber in each provenance ranged from 9.89 to 14.46 GPa, 7.53 to 13.02 GPa, and 33.0 to 68.7 MPa, respectively. Significant geographic differences were found in all examined properties of lumber among the five provenances. No significant relations were found between annual ring width and other properties, suggesting that radial growth rate of L. sibirica trees naturally grown does not always affect reduction on mechanical properties of lumber. Knots and wane were main factors downgrading lumber among the evaluated factors. Tree height, stem shape, and juvenile wood percentage of logs more affected lumber quality of L. sibirica trees from natural forests.