Wood use is an effective strategy for mitigating global warming, and the efficient use of domestic roundwood plays an important role in long-term carbon storage. In this study, carbon stocks in harvested wood products were evaluated based on the "2050 Carbon Neutrality Strategy for the Forest Sector," following the Tier 1 method and the Production Approach defined in the 2019 Intergovernmental Panel on Climate Change (IPCC) Guidelines. Carbon stocks were projected from 2005 to 2050 under one baseline case and two scenarios: a Baseline case, in which domestic roundwood production remains at the historical average level and utilization ratios are maintained; a Scenario 1 (current use), assuming increased roundwood production with allocation according to the historical use ratio of sawnwood, wood-based panels, and paper (2:5:3); and a Scenario 2 (sawnwood-focused), in which all additional roundwood production is allocated exclusively to sawnwood. To examine a policy-relevant application pathway, the additional sawnwood in Scenario 2 was assumed to be used for the reconstruction of aging public educational buildings. The baseline case was used as a reference for evaluating the effects of two scenarios. Among the cases, Scenario 2 achieved the highest carbon storage of 32,772 t C by 2050. Using the additional sawnwood for school reconstruction indicates the potential to sequentially reconstruct all 8,777 aging school facilities nationwide by 2042. Overall, this study highlights the long-term carbon storage potential of domestic roundwood use and the policy potential of applying sawnwood in public construction to support carbon neutrality.

The demand for wood as a raw material, particularly for construction applications, continues to increase. However, the availability of large-diameter timber has declined, leading to the increased use of fast-growing, small-diameter wood species. One approach to overcoming this limitation and improving wood quality to meet construction standards is the application of finger-jointing technology. This study evaluated the strength of finger-jointed wood with different joint positions along the longitudinal direction. A completely randomized factorial design was employed with two factors: joint orientation and joint position. The evaluated parameters included moisture content, specific gravity, modulus of elasticity (MoE), modulus of rupture (MoR), and joint efficiency. The average moisture content ranged from 12.36% to 13.08%, whereas the specific gravity ranged from 0.41 to 0.50. The MoE ranged from 10,044.30 to 17,411.07 MPa, and the MoR ranged from 44.92 to 67.27 MPa. Analysis of variance showed that the treatments had no significant effects on moisture content, specific gravity, or MoE. However, joint position had a significant effect on the MoR, and the post hoc analysis showed significant differences among the joint-position treatments.

This study aims to evaluate the natural durability of imported tropical decking wood without preservative treatment. Five hardwood species, Apitong, Basralocus, Ipe, Malas, and Merbau, were exposed to outdoor conditions for five years. Following AWPA E7 and E18 standards, ground-proximity (H3 conditions) and stake (H4 conditions) tests were conducted to assess resistance to wood-decaying fungi and subterranean termites, including changes in hardness before and after exposure. In the ground-proximity tests, all species exhibited performance ratings > 9.0, indicating negligible deterioration. In contrast, the stake tests revealed that Basralocus, Ipe, and Merbau maintained high resistance, whereas Apitong and Malas showed lower ratings of approximately 7.0, corresponding to a 10%-30% decay. With the exception of Malas, the remaining species experienced little to no termite attacks during the exposure period. Furthermore, Malas and Apitong exhibited significant reductions in hardness, with decreases > 50% in the stake tests. These results suggest that Ipe, Merbau, and Basralocus possess sufficient durability for long-term decking applications, whereas Malas and Apitong have higher risks of decay and mechanical degradation over time.

Neolamarckia macrophylla is an endemic, fast-growing tree naturally distributed across Sulawesi and the Maluku Islands, Indonesia. N. macrophylla is a species used for plantations and community forests; however, its propagation is constrained by limited high-quality seed sources. This study estimated genetic variation, heritability, genetic correlations, and predicted genetic gains for growth and wood-quality traits in a 6-y-old progeny test at Parungpanjang Research Station, Bogor, consisting of 72 families from 10 populations. The traits measured were tree height, diameter at breast height (DBH), tree volume, pilodyn penetration, wood moisture content, wood density, and specific gravity. Family effects were statistically significant for height, DBH, volume, moisture content, and density; block × family interactions were statistically significant for several traits. Stem diameter showed strong genetic correlations with tree height (0.502), volume (0.582), and pilodyn penetration (0.464). Pilodyn penetration was also genetically correlated with wood density (-0.507) and moisture content (0.595). The key selection traits identified were stem diameter and pilodyn penetration, which were strongly correlated with growth and wood traits. Pilodyn penetration is a practical, fast, and non-destructive method that does not require laboratory testing, making selection based on wood quality more efficient. By applying within-family selection at 25% (one best tree per four) combined with a ~40% family retention (43 retained of 72 families), results show meaningful increases in diameter and volume while producing only moderate, correlated changes in wood-quality traits.

This study evaluated the potential of Dioscorea bulbifera L. leaf extract as a natural termiticide against the drywood termite Cryptotermes cynocephalus and as an environmentally friendly alternative to synthetic chemicals. The leaves were macerated in methanol and fractionated into polar (methanol), semi-polar (ethyl acetate), and non-polar (n-hexane) extracts. Toxicity was assessed using a filter-paper contact bioassay over 30 days. Lethal concentration (LC) assays for the semi-polar fraction were prepared across a 1.17%-7.35% gradient corresponding to LC₁₀-LC₉₀. The semi-polar ethyl acetate fraction exhibited the strongest activity; the LC₉₀ dose (7.35%) produced the highest mortality (48%), compared with 24% in the control. This fraction also showed the greatest protective potential, as indicated by reduced feeding-related substrate loss (1.35 ± 5.01%) and surface damage (7.28 ± 25.53%), which are commonly used as proxies for potential wood protection. In comparison, the control treatment exhibited 18.57 ± 5.01% substrate loss and 100 ± 25.53% surface damage. Scanning electron microscopy-energy-dispersive X-ray analysis revealed differences in the surface elemental composition of filter papers treated with different fractions, with the semi-polar fraction showing a more homogeneous distribution of carbon and oxygen than the other fractions. Penetration, transport, and mechanistic interactions were not experimentally confirmed in this study; therefore, these observations are correlative and describe only surface characteristics. These results support the potential of the semi-polar fraction of D. bulbifera leaves as a biodegradable botanical termiticide, as demonstrated by measurable termiticidal activity and reduced feeding-related damage under laboratory conditions.

A post-treatment strategy utilizing a 33.2% (w/w) urea-based formaldehyde scavenger solution was applied to mitigate the long-term formaldehyde emission trend under desiccator conditions associated with energy-efficient cold-pressed plywood used as the core layer in hybrid cross-laminated timber (CLT). The plywood was manufactured by cold-pressing with a phenol-resorcinol-formaldehyde (PRF) adhesive, and the scavenger solution was applied solely to the edge surfaces at three dosages (0.021, 0.063, and 0.105 g/cm²). The long-term emission trends of the treated samples were compared with those of untreated cold-pressed plywood, hot-pressed plywood, and other post-cold-pressing treatments (heat and water). The impact of the scavenger treatment on the physical and mechanical properties of the plywood (density, moisture content, and bending properties) and on the planar (rolling) shear performance of the resulting CLT panels was also evaluated. The treatment reduced the initial (24 h) formaldehyde emission by 65%-68% at dosages of 0.063 and 0.105 g/cm², with the difference between these two dosages being statistically non-significant, indicating saturation of the scavenging effect. Over the 408 h monitoring period, the mean emission of the treated plywood was approximately 89% lower than that of the untreated control, satisfying the Korean E₀ emission class. Neither the bending properties of the plywood nor the planar shear performance of the CLT panels was significantly affected by the treatment. These findings support the use of a urea-based edge treatment as a practical and structurally benign strategy for reconciling energy-efficient cold-pressing with stringent formaldehyde emission requirements in engineered wood production.

Thermal modification is an important treatment process for enhancing the dimensional stability and durability of laminated lignocellulosic products; however, it may adversely affect bonding performance depending on treatment severity and adhesive characteristics. In this study, a mild thermal modification condition (160℃ for 3 h) was selected to achieve a balance between inducing sufficient chemical modification to improve dimensional stability and color uniformity while limiting excessive deterioration of mechanical and adhesion-related properties. This study investigated the effect of mild thermal modification under this condition on the adhesion properties of laminated bamboo. Two citric acid-based adhesives, namely citric acid-starch and citric acid-sucrose, were used at a ratio of 75/25 wt%. Urea formaldehyde (UF) was also used as a comparative treatment. Physical properties and chemical composition of bamboo were evaluated before and after thermal modification. Two-layer laminated bamboo panels were manufactured with citric acid-based adhesives and hot-pressed at 200℃ for 20 min. Adhesion performance was assessed using the delamination rate, bending strength, shear strength, and failure percentage. The results showed that thermal modification at 160℃ for 3 h significantly reduced the wettability of bamboo strips. This treatment negatively affected the shear strength of laminated bamboo bonded with citric acid-sucrose and UF, whereas a positive effect was observed for citric acid-starch-bonded samples. These findings indicated that the selected mild thermal modification condition provides a balanced modification level and is particularly suitable for laminated bamboo bonded with citric acid-starch adhesive.

Significant efforts have been undertaken to convert waste materials into value-added products, such as particleboards, in response to the increasing demand for wood and wood-based materials and to support the panel industry's ongoing transition toward a circular bioeconomy. Therefore, this study aimed to evaluate the feasibility of manufacturing particleboards from organic solid waste (OSW) through the incorporation of wood and bamboo shavings to improve performance. The particleboards were bonded using an isocyanate adhesive at a content of 10% (w/w) and hot-pressed at 160 ℃ for 10 min under a pressure of 4.5 MPa. The results showed that increasing the proportion of wood or bamboo shavings significantly improved board density, dimensional stability, mechanical properties, and resistance to termite attack. Among all formulations, the board composed of 25% OSW and 75% wood shavings (board D) reported the most balanced performance, showing the highest internal bonding strength, enhanced modulus of rupture, and the lowest termite-induced weight loss. This formulation satisfied the minimum requirements for non-structural particleboard based on density, moisture content, thickness swelling, and internal bonding criteria according to JIS A 5908:2003. Particleboards reinforced with bamboo shavings also showed higher stiffness, with modulus of elasticity values exceeding 1,000 MPa. However, comparatively lower resistance to termite attack was reported. In this context, organic waste can be effectively valorized through blending with wood or bamboo shavings to produce environmentally friendly particleboards that show potential for non-structural and interior applications.

A DNA database is crucial for timber's authentication in transparent and sustainable global trade. DNA extraction and applications are critical components of the database development. Wood tissues often contain high levels of metabolites that pose significant challenges for DNA extraction and downstream polymerase chain reaction (PCR) applications. This study used wood and leaf tissues from four populations of Rubroshorea curtisii (Dipterocarpaceae) for modified cetyltrimethylammonium bromide (CTAB) DNA extraction and PCR amplification using trnL-trnF chloroplast DNA primer. The protocol was developed and optimized by incorporating bead-beating methods and enhanced buffer composition (polyvinylpyrrolidone, β-mercaptoethanol) to improve cell lysis and remove inhibitors. The protocol efficiency was evaluated by visualizing the DNA band by electrophoresis, assessing the quality of the DNA sequence chromatogram, and comparing the produced result with the sequence in GenBank (NCBI). This study found visible and consistent DNA bands in leaf tissues, but inconsistent in wood. PCR amplification of the chloroplast trnL-trnF region produced clear and single amplicons from both tissues, showing that the extracted DNA was of sufficient quality for molecular analyses. Sequences produced a clear and readable electropherogram, which subsequent NCBI BLASTn validation confirmed high quality of the result, with 100% query coverage and strong similarity to Dipterocarpaceae reference sequences. In addition to amplification success, sequence alignment showed polymorphic regions, including both single-nucleotide polymorphisms and indels, which differentiated two chloroplast haplotypes corresponding to the island of origin. These results suggest the modified CTAB protocol enables successful PCR amplification and further genetic analyses specifically to verify timber origin in global trade.