This study investigated the resistance of domestic wood species used as wood members in general wood construction and Korean wood cultural properties to the termite Reticulitermes speratus using no-choice and two-choice tests. The results of the no-choice experiment confirmed that hardwood has higher termite resistance than that of softwood. In addition, R. speratus prefers softwood, including Abies holophylla, which has low density, is easy to feed on, and does not contain repellent extracts. In a two-choice test, Zelkova serrata was found to be the most termite-resistant wood species used in wooden cultural buildings. In addition, we investigated the effects of different wood extraction methods and their components on termite resistance. The cold-water extraction of softwood increased the feeding activity of termites; however, the cold-water extraction of hardwood had little effect on the feeding activity of termites. In natural environments with repeated exposure to moisture, such as rainfall, water-soluble extracts present in wood species are relatively more likely to dissolve and removed, making softwood more likely to be damaged by termites than hardwood. Untreated Quercus variabilis showed an extremely weak feeding activity of termites compared with that in other wood species; however, feeding termites with the alcohol-benzene extract of Q. variabilis had no inhibitory effect on their feeding activity. Therefore, we believe that the high density of Oriental cork oak wood inhibits the feeding activity of R. speratus. In contrast, the alcohol-benzene extracts of Z. serrata, Prunus sargentii, and Castanea crenata showed a strong inhibition of the feeding activity of termites.

Wood biomass, such as sawdust, particles, and chips from the wood industry, can be potentially used as a composite product. Chip block pallets (CBP) are composite products that can be produced from industrial wood waste and are in high demand in the logistics sector. Therefore, this study aimed to investigate the production of CBP from teak wood biomass with varying polyurethane contents. In addition, this study analyzed the optimum particle-size composition was determined. The CBP production of CBP be divided into two stages. The first stage evaluated the use of polyurethane adhesive content, whereas the second stage considered the effect of particle size composition. The 9 × 9 × 9 cm³ of CBP with 0.6 g/cm³ target density was fabricated using a cold press. The National Wooden Pallet and Container Association (NWPCA) standards were used to evaluate the density, moisture content, dimensional stability, water absorption, compressive strength (CS), and screw-holding strength (SHS) of our CBP products. The mechanical and physical properties of CBP products were investigated. As a result, the CBP sample prepared using 4-14 mesh particle size and 4.5% adhesive content showed the optimal strength values, such as CS of 14.67 MPa and SHS of 371.50 N. These findings demonstrate that the CBPs derived from teak wood waste closely resemble commercial chip blocks and have the potential to replace wood bearings as pallet pads.

This study investigated the influence of silicon dioxide (SiO₂) addition to particleboard from teak sawdust to reduce water absorption and thickness swelling using standard tests of physical and mechanical properties. The experiment had a completely randomized design with four treatments (SiO₂ concentrations of 5%, 3%, 1%, and 0%), each with three replicates, for a total of 12 conditions. The results showed that 1% concentration was the optimal concentration to reduce both water absorption (32.42% ± 1.78%) and thickness swelling (8.65% ± 1.16%). The product passed the standard tests for physical and mechanical properties, which reduced the cost of the SiO₂ content for particleboard processing. These results suggest that SiO₂ can resist moisture content but may slightly reduce strength.

Litsea elliptica, a Southeast Asian tree with a rich history of medicinal applications, is attracting increasing research attention. This study investigated the effects of leaf maturity and solvent selection on the extraction of bioactive compounds from L. elliptica leaves, specifically with regard to their antioxidant activity. 2,2'-Azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) method was employed to quantify the free radical scavenging capacity of L. elliptica leaf extracts prepared using three different solvents (n-hexane, ethyl acetate, and ethanol) at three different leaf stages (tender, immature, and mature). These results highlight the significant effects of leaf maturity and solvent selection on the extraction of phenolic compounds and flavonoids from L. elliptica leaves. Ethanol is the most effective solvent for the extraction of bioactive compounds, particularly from mature leaves. The ethanol extraction of tender leaves demonstrated potential for optimizing the antioxidant content. Further research is necessary to investigate the specific factors influencing the observed differences in antioxidant activity between leaves of varying ages and the potential impacts of other bioactive compounds present in the leaves.

Teak tree breeding programs have been conducted over the last several decades in various locations throughout Indonesia. These programs have produced superior teak clones with growth increments > 3 cm diameter at breast height. The wood quality of this clonal teak must be evaluated to determine the final use of these trees and the success rate of the teak breeding programs. In this study we investigated the physical condition (reflected in wood color and heartwood percentage), physical properties (moisture content, basic density, shrinkage, and tangential/radial shrinkage ratio), and mechanical properties (modulus of elasticity, modulus of rupture, compressive strength parallel and perpendicular to grain, hardness, and cleavage strength) in 20-year-old clonal teak planted in Ngawi, East Java. The parameters were measured in the axial (bottom, middle, and top) and radial (near pith, middle, and near bark) directions and according to the British Standard 373:1957. The results showed that axial variation significantly affected the wood color (L^*, a^*, and b^*), basic density, radial shrinkage, modulus of elasticity, and compressive strength parallel to the grain. Besides, the radial variation had a significant effect on wood color (L^*), basic density, modulus of elasticity, modulus of rupture, compressive strength parallel and perpendicular to the grain, hardness, and cleavage strength. Based on these results, it can be concluded that the teak breeding program has been highly successful.

Two first-generation progeny trials of Ficus variegata Blume were planted in Yogyakarta, Indonesia, consisting of 17 families from the provenances of West Nusa Tenggara (WNT) and 19 families from the provenances of Cilacap-Pangandaran (C-P), respectively. The trials were evaluated after 10 years for growth characteristics [diameter (D), tree height (H) and stem volume (V)] and wood properties [stress-wave velocity (SWV) and Pilodyn penetration (P)]. Genetic variation, the coefficient of additive genetic variation (CV_A), and heritability estimation were analyzed. Subsequently, genetic correlation between traits was estimated. The analysis of variance showed that there were significant differences in growth characteristics and wood properties in the WNT families, with significance observed across most factors except for height and P in the C-P families. The CV_A in growth characteristics (D, H, V) was higher than for wood quality (SWV and P) in WNT and C-P families. Estimated family heritability (h²_f) for growth characteristics, SWV, and P were high in the WNT families but moderate in the C-P families showing that genetic variation in the observed traits was more additive in the WNT families. The positive estimated genetic correlations between growth characteristics in two progeny trials, and the moderate to strong negative genetic correlation between D and P and also between P and SWV showed that growth characteristics and wood quality can be genetically improved simultaneously by using D as a selection criterion is an appropriate breeding strategy for F. variegata.

Shoot waste refers to the parts of trees that are not yet optimally utilized. In this study, we aimed to utilize shoot waste of fast-growing teak (FGT) extracted from the community forest in Wonosari, Gunungkidul, Yogyakarta Special Region, Indonesia by converting it into charcoal, followed by further conversion into activated carbon. This study was conducted with two treatment factors of the activation process, including thermal treatment (750℃, 850℃, and 950℃) and heating period (30, 60, and 90 min), to determine the best condition for the activation process. Our results indicated a significantly effect of the interaction between thermal treatment and heating period on the moisture content, volatile matter content, ash content, fixed carbon content, and adsorption properties of the produced activated carbon. The highest iodine adsorption capacity of activated carbon is 1,102.57 mg/g, which was produced by thermal treatment at 750℃ and heating period of 30 min. This result fulfilled the Indonesian National Standard (SNI 06-3730-1995 quality standard). Furthermore, the quality parameters of the produced activated carbon include: moisture content of 6.13%; volatile matter content of 17.27%; ash content 5.24%; fixed carbon content of 77.49%; benzene removal efficiency of 8.43%; and methylene blue adsorption capacity of 69.66 mg/g. Based on this study, we concluded that shoot waste of FGT could be classified as a prospective material for developing activated carbon for industrial application.

Timber industry waste is being examined for cellulose manufacturing to give important benefits. The study's goal is to investigate the properties of cellulose powder derived from sawdust waste after it has been reinforced with ferrous-ferric oxide nanoparticles (Fe₃O₄-NPs). Sawdust cellulose powder was produced from Sengon (Albizia chinensis) wood waste in this study. The crushed sawdust waste is handled with alkalization and bleaching. Cellulose powder is then reinforced with Fe₃O₄-NPs at 10 wt.%, 20 wt.%, and 30 wt.%. The magnetic cellulose powder was analysed by X-ray diffraction, Fourier Transform Infrared, scanning electron microscopy morphology, magnetic vibrating sample magnetometer, Brunauer-Emmett teller, and adsorption tests for Methylene Blue and Congo Red dyes. Structure study identifies sawdust as cellulose 1β, with peaks at 14°, 16°, and 22° diffraction angles. The addition of Fe₃O₄-NPs reduces the crystalline index of sawdust cellulose powder from 68.50% to 63.38%, and functional group bond analysis revealed many peak shifts indicating a change in the chemical bonds of magnetic cellulose powder. Incorporating Fe₃O₄-NPs into sawdust cellulose powder confers magnetic and superparamagnetic properties to the sawdust cellulose. Similarly, the surface texture of magnetic cellulose seems rougher as the surface area increases. These parameters imply a 31.8% increase in Congo Red adsorption, using adsorption kinetics based on the pseudo-first-order model.