Bamboo cracking is primarily attributed to the influence of moisture on its structure. Natural-speckle digital image correlation (DIC) was employed to characterize tangential shrinkage in cross-sections, using parenchyma cells as intrinsic speckle patterns. Shrinkage behavior during the 24 h drying process at a temperature of 103 °C across the external, middle, and internal layers was comparatively analyzed in bamboo nodal regions (NR), internodal regions (IR), and transitional zones (TZ, i.e., node–internode interfaces). Moisture had the most pronounced effect on NR, which consistently exhibited the highest moisture content and shrinkage ratios during the drying process. Notably, the drying shrinkage of the external layer was significantly greater than that of other layers. Specifically, the drying shrinkage strain ratio of the external layer of NR is 3.02 times higher than that of the internal layer, while for IR, it is 3.60 times higher. Furthermore, the external layer of NR exhibits substantial deformation during the initial stages of drying, with a drying shrinkage strain ratio of 5.96% for 2 h. The results demonstrated that shrinkage deformation in bamboo nodes was significantly greater than in other regions, offering valuable insights for developing strategies to mitigate bamboo cracking.

This study examined spatial and temporal thermal performance and energy consumption. The temperature distribution in the running period was monitored in test rooms with integrated electric- and hot water-heated floors. The short- and long-term energy consumption of the two heating systems were recorded and compared. The results indicated that the integrated electric heating system generated higher temperatures for indoor air and on the exterior surface of the wooden floor than the hot water heating system; meanwhile, the difference in the mean temperatures of the exterior and rear surfaces of the electric-heated floor was 2.44 °C, while that of the hot water-heated test room was 13.25 °C. The efficient structure of the integrated electric heating system saved 22.97% energy compared to the hot water system after short-term (7 h) charging and reaching a dynamic balance, and it efficiently increased the energy utilization rate to 11.81%. After long-term charging, the daily energy consumption of the integrated electric heating system consumed much less energy than the hot water system every month. The integrated electric heating system saved 62.55% and 34.30% of energy in May and January, respectively, and consumed less than half of the energy the hot water system consumed in the less cold months. Therefore, a high-efficiency and energy-saving integrated electric-heated floor could be a potential indoor heating solution.

To further improve the manufacturing process and product performance of decorated bamboo filament board, the Box–Behnken response surface analysis method was used to analyze the correlation between the hot-pressing parameters and surface bonding strength, and the optimal process optimization parameters were obtained. In addition, the wettability and color of each group of samples were tested. The results show that the optimum process parameters of decorated bamboo filament boards were 130 °C, 165 s and 2.00 MPa, and the surface bonding strength was 1.58 MPa. The relative error between the measured value and the predicted value was less than 5%. The contact angle of the bamboo filament after hot pressing was higher than without hot pressing. However, there was no correlation between wettability and the hot-pressing parameters. There was no effect on the change in bamboo surface color. This indicates that the temperature range selected in this study meets the requirements of surface color control in production.

The finger-joint technique is an effective and economical method for producing bamboo scrimber composites for structural engineering and construction applications. This study investigates the failure modes and mechanical strength of finger-jointed bamboo scrimber specimens and composite beams loaded parallel and perpendicular to the finger profile orientation. Results indicate that the primary failure mode in finger-jointed bamboo scrimber specimens is damage to the finger-joint area. In V-type composite beams, primary failure was observed as the separation of laminated boards and finger joints, while in H-type beams, large cracks formed and expanded alongside finger joint damage. No statistically significant difference was observed in the modulus of elasticity (MOE) and modulus of rupture (MOR) between the two types of finger-jointed bamboo scrimber. However, the MOR of the finger-jointed bamboo scrimber specimens decreased significantly, by more than 50% compared to the control, while the MOE increased. The ultimate load capacity and displacement of the V-type beams were higher. Under bending, the V-type beams demonstrated elastic deformation, whereas the H-type beams exhibited initial elastic deformation followed by elasto-plastic deformation. Strain distribution along the height of both beam types remained linear, consistent with the plane-section assumption.

The effects of periodic hot-press drying on drying behavior and mechanical damage to Chinese fir lumber were investigated by taking the heating platens’ temperature (T_P) and compression ratio (R_c) as experimental factors. The temperature and pressure inside lumber were analyzed during drying process. The results were as follows. The drying rate of lumber was significantly increased with increasing T_P and R_c. Scanning electron microscope (SEM) micrographs showed that bordered pit membranes, cross-field pits, middle lamella between adjacent cells, and tracheid walls were damaged after drying, and the damage became more severe with higher T_P and R_c. Detachments between ray parenchyma cells and tracheids were observed at 170 °C. Nitrogen-adsorption measurement results demonstrated that more cell wall pores in the 2.5~6.2 nm pore diameter range were generated at higher T_P, resulting in an enlarged specific surface area and pore volume of cell walls. These structural changes contributed to accelerating moisture migration and decreasing the drying time. Furthermore, fluctuating pressure inside lumber was the main driving force leading to moisture migration and cell tissue damage in lumber during drying. The influence of T_P on internal temperature (T_M) and pressure (P_M) was greater than R_c. With the increase in T_P from 130 to 170 °C at the R_c of 10%, the maximum T_M and P_M were increased by 30.90% and 39.84%, respectively. However, T_P should not be too high to prevent the formation of macro-cracks caused by high pressure, which may significantly affect wood’s mechanical properties. These results provide theoretical support for periodic hot-press drying processes’ improvement and high-value utilization of Chinese fir.