This study aimed to investigate the effects of growth ring width, height from the tree base, and loading direction on the transverse compressive strength of Japanese larch wood, which is commonly used in wood structures in China. Plantation wood is often used to replace natural forest woods for reconstruction purposes, despite significant differences in properties (e.g., growth rings, density, strength) between them. The ends of transversely compressed wood members in such structures are prone to damage by breaking or crushing. A transverse compressive test was conducted following Chinese national standards, which revealed the following key findings. (1) There was a significant difference in the transverse compressive strength of wood with different growth ring widths (p < 0.05). The radial and slant compressive strength of wood increases with growth ring width, while the tangential compressive strength decreases as growth ring width increases. (2) The transverse compressive strength of wood decreases as the height from the tree base increases. The radial, tangential, and slant compressive strength at a lower height were 18.39%, 22.58%, and 18% higher than those at a greater height in the stem, respectively, with significant differences at the 0.05 level. (3) The load–displacement curve of Japanese larch wood under radial and slant compression follows a “three-segment” form. In contrast, the load–displacement curve of tangential compression is a continuous curve that drops sharply upon reaching its highest point. (4) There is a significant difference in the transverse compressive strength of Japanese larch wood in different loading directions when growth ring width and height from the tree base are constant (p < 0.05), which fall into order as tangential > radial > slant.

In order to evaluate the physical and mechanical properties of plantation Japanese larch wood, various physical and mechanical indicators were measured with reference to Chinese national standards. The characteristics of the growth ring on the end face of wood samples were captured, with the mean latewood percentage being 21.4% and the mean ring width being 3.24 mm. Relationships between growth ring characteristics, latewood percentages, and the physical and mechanical properties of the plantation Japanese larch wood were investigated. The results revealed that it is most appropriate to use growth ring width to evaluate MOE and MOR, and to use latewood percentage to evaluate air-dry density, radial air-dry shrinkage, IBS and UTS. Regression analysis confirmed that air-dry density (R² = 0.99), radial shrinkage (R² = 0.97) and UTS (R² = 0.96) had significant positive correlations with latewood percentage, while MOE (R² = 0.88) and MOR (R² = 0.90) had significant negative correlations with RW. IBS was not significantly related to either characteristic. RW can be used to define juvenile wood and mature wood, with the dividing ring width being 4.85 mm. There is a large difference in MOE and MOR between the two wood types.

Bamboo scrimber (BS) has been emerging as a promising construction material prepared from natural bamboo due to its high mechanical strength. However, the variability of the properties of bamboo scrimber is large, which limits the reliability assessment of bamboo scrimber in engineering applications. In this study, the variability of mechanical properties and dimensional stability of bamboo scrimber prepared by units pretreated at different temperatures (denoted as BS-150 and BS-200 for 150 °C and 200 °C, respectively) were compared and probabilistically analyzed using normal, lognormal, and Weibull distribution models. The results showed that BS-200 had a significantly lower thickness swelling rate (TSR), modulus of rupture (MOR) and shear strength (SS), with the modulus of elasticity (MOE) remaining essentially unchanged compared to BS-150. Probabilistic analysis revealed that the MOR, MOE, and TSR of BS-150 followed a lognormally distribution, and the shear strength was normally distributed. In contrast, the MOR, MOE, SS, and TSR of BS-200 all exhibited lognormal distributions. Meanwhile, the variability in TSR and SS for BS-200 was significantly reduced. The results provide a data base for the engineering application of bamboo scrimber and a new research idea for the evaluation of properties of forest biomass-based materials based on probabilistic analysis.