The genus Melia is known for its secondary metabolites and recently, this genus is being explored for its timber. There are vast differences among its species. For instance, Melia azedarach is reported to be invasive and while another species, M. dubia, has diverse utility with complex germination and regeneration characteristics. Researchers globally have been working on various aspects of this genus; In this study, using topic modelling and science mapping approach, we attempted to understand research facets on this genus. The literature corpus of the Web of Science database was explored using a single keyword-\"Melia\" which yielded 1523 publications (1946-2022) and after scrutiny metadata of 1263 publications were used in the study. Although nine individual species were cited in the publications, only three species are accepted viz., M. dubia, M. azedarach, and M. volkensii. This implies taxonomic uncertainty, with potential confusion in assigning scientific findings to particular species. Thus, a taxonomic relook on this genus is warranted for a better assessment of the economic utility in many countries. More importantly, our results indicate that the research interests have recently shifted from the secondary metabolite constituents towards growth, biomass, wood properties, germination, plantation, and green synthesis. The shift in research focus toward wood properties of Melia sp. can impact the wood demand-supply at a global scale owing to its fast growth and the possibility of cultivation over a wider geographical range.

Driven by climate change and the need for a more sustainable construction sector, policy is increasingly demanding and promoting timber hybrid construction methods. In the German state of Baden-Württemberg, every new public building has to be of timber or timber hybrid construction (Holzbauoffensive BW). The objective of multi-story buildings with large floor spans can only be achieved in a resource-efficient way by hybrid constructions combining timber and steel components. A research project recently completed at the Karlsruhe Institute of Technology was aimed at the development and systematic investigation of hybrid bending beams in which an advantageous combination of the materials steel and timber is used. For this purpose, steel profiles are integrated into timber cross-sections in a shear-resistant manner by adhesive bonding. As part of the experimental, numerical and analytical investigations, different cross-sections of steel and timber, as well as different construction materials, were considered (GL24h, LVL48p, LVL80p, S355 and S420). The results of large-scale four-point bending tests illustrate the potential of this new hybrid construction method. Depending on the geometry and material combinations tested, the bending stiffness could be increased by up to 250%, and the load-carrying capacity by up to 120%, compared to a glulam beam with identical dimensions.

This paper presents a numerical investigation of the flexural behavior of timber beams externally strengthened with carbon-fiber-reinforced polymer (CFRP) sheets. At first, the accuracy of linear elastic and elastic-plastic models in predicting the behavior of bare timber beams was compared. Then, two modeling approaches (i.e., the perfect bond method and progressive damage technique using the cohesive zone model (CZM)) were considered to simulate the interfacial behavior between FRP and timber. The models were validated against published experimental data, and the most accurate numerical procedure was identified and subsequently used for a parametric study. The length of FRP sheets varied from 50% to 100% of the total length of the beam, while different FRP layers were considered. Moreover, the effects of two strengthening configurations (i.e., FRP attached in the tensile zone only and in both the tensile and compressive zones) on load-deflection response, flexural strength, and flexural rigidity were considered. The results showed that elastic-plastic models are more accurate than linear elastic models in predicting the flexural strength and failure patterns of bare timber beams. In addition, with increasing FRP length, the increase in flexural strength ranged from 10.3% to 52.9%, while no further increase in flexural strength could be achieved beyond an effective length of 80% of the total length of the beam. Attaching the FRP to both the tensile and compressive zone was more effective in enhancing the flexural properties of the timber beam than attaching the FRP to the tensile zone only.

There are remarks on diverse types of timber structures in the tropics. This paper examines several case histories in Sri Lanka, focusing on the culturally varied and ecologically diverse traditional buildings with wood used for construction. The main objective was to gather data and document the knowledge on wood preservation. Information was gathered through face-to-face interviews with 270 individuals\' reference to 138 structures. A holistic analysis was performed to understand the techniques used to overcome the degradation mechanisms and state of conservation. The demographic profile of the informants was evaluated and cross-relationships on the tabulated data were analyzed by SPSS statistical software following the snow-balling sampling technique. There were three main preservation techniques identified from the open-ended questions namely, wood kept under smoke pits, wood kept under paddy field mud, and wood kept under the river banks. Preserving wood by keeping it under paddy field mud (49.62 %) was the highest recorded answer. The most obtained material matrix of preservation was plant origins (48.88 %). For generations, people have transmitted traditional and cultural practices through oral knowledge. The results conclude this knowledge places a high value on protecting construction technologies and applications while preserving biodiversity. Unfortunately, by today this technology has started extinct. The results revealed the importance of social norms and cultural perceptions as a set of valuable information that was practiced with a great history in a tropical country.

Using an extended full-cycle carbon model from the Faustmann framework, which allows for management strategies of several uses concurrently implemented in the same area of forest, this paper investigates the selection of management objectives that are beneficial and optimal for forest plantations in Vietnam. Three scenarios are considered: Scenario 1 investigates the management objective of maximizing the land economic value (LEV) of timber as a single production. Scenario 2 investigates the joint production of timber and bioenergy sources. Scenario 3 analyzes the joint production of timber, bioenergy production, and carbon sequestration. The findings reveal that if growers pursue a timber management objective (Scenario 1), the farming business only provides considerable benefits under the government-subsidized credit scheme of 8.4%. For a higher non-subsidized interest rate of 15.24% of commercial banks, such gains reduce substantially and become negative value under the mean interest rate of 19.08% of private credit sources. Altering the management objective to a joint production of timber and raw bioenergy production (Scenario 2) will boost the LEV by a moderate level, but at the expense of timber production and thus carbon stock. However, the reduction tendency of timber and carbon balance is not substantial due mainly to the relatively small proportion of bioenergy production compared to timber production; therefore, decision-making frameworks targeting carbon uptake may be capable of incorporating such levels of confliction. Further internalizing the carbon value of the forest into management objectives generally leads to a longer rotation length, thus improving both carbon sequestration and income gains. Shifting the current timber-dominant management objective to a joint production of timber and bioenergy sources, or, alternatively, a joint production of timber, bioenergy production, and carbon sequestration when the carbon market is emerging, is a good alternative strategy for forest management in Vietnam.

Forest-grassland ecotones are a mosaic of grassland, savanna, and upland forest. As such, landowners may have opportunities to choose to manage their lands for multiple objectives. We estimated the economic returns from managing forest and rangeland in southeastern Oklahoma, USA to produce different combinations of timber, cattle forage, and white-tailed deer (Odocoileus virginianus Zimmermann) browse for a 40-year period. We further conducted a survey to understand landowner perceptions of obstacles to adopting active management that involve timber harvest and prescribed fire. The highest net return was obtained from the treatment with harvested timber that was burned every four years (uneven-aged woodland/forest) because it had the greatest gross return from a combination of timber (46%), cattle forage (42%), and deer browse (11%). The return from this treatment was greater than that for managed for timber only (closed-canopy forest) or prioritizing cattle and deer (savanna). Survey results suggested that landowners were aware of the benefits of active management but that the majority (66%) considered cost a major obstacle in the management of their forest or rangeland. In particular, women forestland owners and older landowners considered cost an obstacle. Our findings advocate integrated timber, cattle, and deer management as the best economic strategy within the forest-grassland ecotone and for targeted outreach and landowner education related to the benefits of active management.

There is a limited comprehensive analysis of the effectiveness of adopted carbon mitigation strategies for buildings over their life cycle, that are concerned with temporal perspectives of emissions. Accordingly, this paper explores a life cycle assessment (LCA) to address the concerns regarding mitigating the carbon footprint of a UK timber-frame low-energy dwelling. In particular, it aims to investigate the potential greenhouse gas (GHG) emission reduction in terms of three different heating and ventilation options, and to analyze the influence of decarbonization of electricity production as well as the technological progress of the waste treatment of timber on the building\'s environmental performance. Thus, the whole life‑carbon of the building case studies was evaluated for a total of eight investigated prospective scenarios, and they were compared to the LCA results of the baseline scenario, where the existing technology and context remained constant over time. Results show that using a compact heat pump would lead to a significant whole life-cycle emission reduction of the dwelling, by 19 %; while GHG emission savings can be reinforced if the assessed systems are employed simultaneously with grid decarbonization, exhibiting a 25 %-60 % reduction compared to the baseline scenario. Moreover, technological changes in the waste treatments of timber products could substantially reduce the buildings\' embodied emissions, representing 3 %-23 %. From these emission-saving measures, the contribution of material efficiency strategies to achieve more embodied carbon savings should be highlighted in future construction practices.

Forests are crucial sustainable sources of natural ecosystems and contribute to human welfare. Cunninghamia lanceolata (Chinese fir) is an economically important conifer and occupies the largest area in China that produces global wood resources. Although Chinese fir has high economic value in China, little information is known regarding its mechanisms of wood formation. Therefore, transcriptome analysis was conducted to study the gene expression patterns and associated timber formation mechanisms in Chinese fir at different stand ages. In the present study, a total of 837,156 unigenes were identified in 84 samples from Chinese fir (pith and root) at different stand ages via RNA-Seq. Among them, most of the differentially expressed genes (DEGs) were significantly enrichment in plant hormone signal transduction, flavonoid metabolism pathway, starch and sucrose metabolism, and MAPK signal transduction pathway, which might be associated with the diameter formation in Chinese fir. The DEGs in these pathways were analyzed in Chinese fir and were related to lignin synthesis, cell wall formation and cell wall reinforcement/thickening. These genes might play an important role in regulating timber formation/growth in Chinese fir. In addition, certain transcriptome factors (TFs) related to Chinese fir timber formation were identified, including WRKY33, WRKY22, PYR/PYL, and MYC2. Weighted co-expression network analysis (WGCNA) showed that glucan endo-1,3-beta-d-glucosidase was a hub gene significantly correlated with the growth-related genes in Chinese fir. Sixteen key genes that related to diameter regulation in Chinese fir were verified by qRT-PCR analysis. These key genes might have a fine regulatory role in timber formation in Chinese fir. Our results pave the way for research on the regulatory mechanisms of wood formation, and provide an insight for improving the quality production of Chinese fir.

This article contains an experimental dataset related to the mechanical properties of Canadian small clear spruce-pine-fir wood. Motivated by the necessity of shading light on the orthotropic mechanical behavior of clear specimens of two of the most common wooden grades used for the manufacturing of cross-laminated timber panels in North America, a comprehensive experimental campaign on small clear spruce-pine-fir wood specimens, based on ASTM D143-22, has been conducted in the Department of Wood Science of the University of British Columbia. A total of 690 specimens from both visually-graded number 2 and machine-stress rated 2100fb 1.8E spruce-pine-fir wood were tested in compression, tension, and shear, following the directions parallel- and perpendicular-to-the-grain. For each test, the force and the deformation were recorded on-line through an MTS software before being stored in a hard drive disk unit as text files at the end of the test. Text files were then post-processed using a MATLAB routine to generate stress-strain data points, ultimate strength, and modulus of elasticity. Additionally, probability distributions of ultimate strength and modulus of elasticity of specimens were plotted. A Kolmogorov-Smirnov goodness-of-fit test was used to fit these data using either Burr, Gumbel, or Weibull distribution. In overall, the dataset presented in this work can be used in the finite-elements modelling of the structural behavior of timber connections or the local mechanical behavior of timber elements. This dataset can also be used to get a grasp and asses the variability in the mechanical properties of Canadian small clear spruce-pine-fir wood.

The article presents an analysis of the static work of bent solid-wood beams reinforced with FRCM-PBO (fiber-reinforced cementitious matrix-p-phenylene benzobis oxazole) composite. In order to ensure better adhesion of the FRCM-PBO composite to the wooden beam, a layer of mineral resin and quartz sand was applied between the composite and the wooden beam. Ten wooden pine beams with dimensions of 80 × 80 × 1600 mm were used for the tests. Five wooden beams, unreinforced, were used as referenced elements and another five were reinforced with FRCM-PBO composite. The tested samples were subjected to a four-point bending test in which the static scheme of a simply supported beam subjected to two symmetrical concentrated forces was used. The main purpose of the experiment was to estimate the load capacity, the flexural modulus and the maximum bending stress. The time needed to destroy the element and the deflection were also measured. The tests were carried out based on the PN-EN 408: 2010 + A1 standard. The material used for the study was also characterized. The methodology and assumptions adopted in the study were presented. The tests confirmed a significant increase in destructive force by 141.46%, maximum bending stress by 118.9%, modulus of elasticity by 18.32%, time needed to destroy the sample by 106.56% and deflection by 115.58% compared to the reference beams. The unusual method of wood reinforcement presented in the article can be considered as innovative, characterized not only by a significant load capacity margin exceeding 141%, but also by simplicity of application.