Bamboo harvesting residues are wastes by-products of bamboo industries that contain holocellulose for about 63.14% to 70.71%, which often be discarded, incinerated or buried. In this study, carboxymethyl cellulose was prepared from bamboo harvesting residues (bamboo-branch and bamboo-tip) as raw materials. The chemical composition of bamboo harvesting residues, the viscosity and degree of substitution of carboxymethyl cellulose were determined. Carboxymethyl cellulose obtained was further characterized and compared by means of FTIR, SEM, XRD and TG. Results showed that under the optimized identical conditions, the viscosity and degree of substitution of carboxymethyl cellulose from bamboo-branch and bamboo-tip were 6.0 and 78.9 mPa·s, 0.75 and 0.89, respectively. Carboxymethyl cellulose obtained from bamboo-tip displayed a lower crystallinity and a better thermal stability as compared to synthetic carboxymethyl cellulose obtained from bamboo-branch and bamboo-culm.

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) has been an important afforestation species in northeast China. It has obvious defects of buckling and cracking easily, which are caused by its chemical components. Trametes versicolor (L.) Lloyd, a white-rot fungus, can decompose the cellulose, hemicellulose, and lignin in the wood. White-rot fungus was used to biologically degrade Chinese fir wood. The effects of different degradation time on the Chinese fir wood’s mechanical properties, micromorphology, chemical components, and crystallinity were studied. The results showed that the heartwood of Chinese fir was more durable than the sapwood and the durability class of Chinese fir was III. Trametes versicolor (L.) Lloyd had a greater influence on the mechanical properties (especially with respect to the modulus of elasticity (MOE)) for the sapwood. Trametes versicolor (L.) Lloyd degraded Chinese fir and colonized the lumen of various wood cell types in Chinese fir, penetrated cell walls via pits, caused erosion troughs and bore holes, and removed all cell layers. The ability of white-rot fungus to change the chemical composition mass fraction for Chinese fir was: hemicellulose > lignin > cellulose. The durability of the chemical compositions was: lignin > cellulose > hemicellulose. The crystallinity of the cellulose decreased and the mean size of the ordered (crystalline) domains increased after being treated by white-rot fungus.

The elastic constants play a crucial role in the rigidity designing and numerical model building of bamboo, thus it will enhance the accuracy of numerical model to obtaining the elastic constants fully and accurately. In this paper, the elastic properties of bamboo, bamboo fiber and bamboo parenchyma were studied systematically, and the elastic constant map of bamboo was plotted. The results would provide significant theoretical foundation for the numerical simulation of bamboo and the design and manufacture of new biomimetic materials, meanwhile the experimental design would also provide important reference for the test of other bamboo species and biologic materials.

Thinning silviculture is a forestry measure that can improve forest ecosystems and stand structure. Thinning can impact the properties and quality of poplar wood. This study investigated the effects of three different thinning intensities on the fiber morphology and crystallinity of poplar wood, providing a theoretical basis for the cultivation and rational processing of poplar plantations. The results indicated significant differences in the proportion of wet heartwood area among different thinning intensities. With increased thinning intensity, the wet heartwood area proportion rose, while it decreased with wood height under the same thinning intensity. Fiber length increased with thinning intensity, reaching a 16% increase at 50% thinning, as well as with sampling height. Fiber width grew with thinning intensity, initially widening, and then narrowing with height. Cell wall thickness first increased and then decreased with thinning intensity, peaking at 50% thinning. The fiber length-width ratio increased with thinning intensity and initially increased then decreased with height. The fiber-diameter-cavity ratio also increased with thinning intensity and height. Crystallinity showed a trend of first increasing and then decreasing with tree height, peaking at breast height, and it was higher in normal wood than in wet heartwood under the same thinning intensity.