Dalbergia cultrate, Dalbergia latifolia, and Dalbergia melanoxylon are precious and valuable traded timber species of the genus Dalbergia. For chemotaxonomical discrimination between these easily confused species, the total extractive content of the three wood species was determined using four different organic solvents. Fourier transform infrared (FTIR) spectroscopy was used to analyze functional group differences in the extractive components, inferring the types of principal chemical components according to characteristic peak positions, intensities, and shapes. Gas chromatography-mass spectrometry (GC-MS) was carried out a detailed characterization of the extractive components. The relative content of individual chemical components was determined by area normalization. Results revealed differences in the chemical components and total and individual extract contents of the three Dalbergia species, indicating that FTIR and GC-MS spectroscopy can be applied to identify and discriminate between Dalbergia cultrate, Dalbergia latifolia, and Dalbergia melanoxylon.

Soybean meal-based adhesives are attractive potential environmentally friendly replacements for formaldehyde-based adhesives. However, the low strength and poor water resistance of soybean meal-based adhesives limit their practical application. This study was conducted to develop a natural fiber-reinforced soybean meal-based adhesive with enhanced water resistance and bonding strength. Pulp fiber (PF), poplar wood fiber (WF), and bagasse fiber (BF) were added as fillers into the soybean meal-based adhesive to enhance its performance via hydrogen bonding between the PF and the soybean meal system. The enhanced adhesive exhibited a strong crosslinking structure characterized by multi-interfacial interactions wherein PF served as a bridging ligament and released residual stress into the crosslinking network. The crosslinked structure and improved interfacial interactions were confirmed by Fourier transform infrared (FTIR) spectrophotometry, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) measurements. Plywood bonded with 4 wt % PF-containing soybean meal-based adhesive exhibited a wet shear strength (1.14 MPa) exceeding that of plywood bonded with the control group by 75.4% due to the stable crosslinking network having efficiently transformed stress and prevented the permeation of water molecules.

Fibers of four tree species, moso bamboo and wheat straw were modified in situ with organo-montmorillonite (OMMT). The characterization of the physical and mechanical properties of the resulting composites showed that OMMT can be synthesized in situ within the fibers’ matrix. Some individual OMMT layers were clearly observed, while some agglomeration was seen on the fiber surface. After blending with poly(lactic acid) (PLA), redistributions of OMMT in the PLA matrix occurred and most properties of the composites were improved. The modification effect of Chinese fir was the best while that of moso bamboo and straw wheat was rarely poor because of their different chemical components, anatomical structures and densities. In short, a higher lignin content, large diameter of pits and lower density contributed to the improved properties of the wood plastic composites (WPCs) with the participation of OMMT.

In this study, the odors of two types of softwood species, namely southern yellow pine (Pinus spp.) and China fir (Cunninghamia lanceolata (Lamb.) Hook.), were identified and extracted with ethanol–toluene for the removal of extractives. The odorous components of neat and extracted wood were identified via gas chromatography-mass spectrometry/olfactometry (GC-MS/O). The results showed that about 40 key identified volatile compounds (peak area above 0.2%) were detected from the GC-MS data, and more than 50 kinds of odorants were identified using GC-O. The time concentrated on was from 15 to 33 min for GC-O, which was different to the time concentrated on for GC-MS. The amounts of both volatile compounds and odorants in pine were more than in fir. After extraction, the amounts and intensities of some odorants decreased, while some remained. However, the extraction process resulted in benzene residue and led to increased benzene odor.

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.