Study on basic wood properties of critically endangered species Syzygium album

Syzygium album is a critically endangered species, and the wood basic properties haven’t been reported. Therefore, this paper analyzes the wood from the anatomical characteristics, physical properties, and secondary components. The results showed that observed S. album wood of a 46-year-old tree is diffuse-porous to semi-diffuse-porous wood. The maximum vessel tangential diameter is 127.47 μm, which is found at the beginning of the earlywood. The wood rays are heteromorphic type I and II, and the multi-column part is mostly 3 cells wide. In physical properties, the air-dry density is classified as “heavy”, whereas its air-dry and full-dry differential dry shrinkage are “small” and “medium”, respectively. This indicates that the wood performs better when dried. The content of benzene-ethanol extract from S. album wood is 2.10%. The benzene-ethanol extracts were analyzed by GC-MS, and the main components are 2,6,11,15-tetramethylhexadecane (3.29%), eicosamethyl cyclodecasiloxane (10.02%), octadecamethyl cyclononasiloxane (7.43%), and tetracosamethyl cyclododeca- siloxane (3.60%), etc.

Study of the discoloration behaviour of teak wood (Tectona grandis Linn. fil.) caused by simulated sunlight

To investigate the discoloration behaviour of teak (Tectona grandis Linn. fil.) during irradiation, teak veneer specimens were exposed to xenon lamp light simulating sunlight for 80 h and subsequently analysed with a colorimeter. The colour changes were explained by recording Fourier transform infrared (FTIR) and gas chromatography-mass spectrometry (GC-MS) spectra at different exposure times. Forty hours of simulated irradiation marked a key point in the colorimetric analysis. During irradiation of 40 h, the increase in the CIELAB parameters ∆a* and ∆b* originated from the generation of carbonyl derivatives that were determined by FTIR analysis. Besides that, by combining GC-MS and microscopic analyses, the decrease in ∆L* in the first 20 h resulted from extractives migrating from the interior to the surface, and that the subsequent increase in ∆L* mainly arose from volatilization of the extractives. Additionally, the decrease in ∆b* after another 40 h of irradiation was mainly due to decreasing volatile extractive contents. Our conclusion reveals the causes of photo-induced discoloration in teak.