Near-infrared spectral signatures differentiate blue stain and brown rot fungi in conifer and broadleaf trees

Colonization by blue stain and brown rot fungi affects timber quality in distinct ways. Blue stain fungi cause discoloration without reducing wood properties, while brown rot fungi degrade wood tissues, resulting in brittleness and brown coloration. Given these chemical differences, we investigated whether near-infrared spectroscopy (NIRS) could distinguish between these fungal types. We hypothesized that early fungal attack would produce unique spectral signatures, allowing for rapid identification. Wood disc samples were collected from white spruce, lodgepole pine, and trembling aspen in Fox Creek, northwest Alberta, Canada, ca. 4 months after a wildfire. The trees were colonized by fungi associated with blue and brown sapwood discoloration and analyzed using NIRS. In white spruce, we found consistent and significant absorbance differences between blue- and brown-discolored sapwood across each 100 nm segment. In lodgepole pine, the most distinct differences occurred in the 1650–1750 nm, 2050–2150 nm, and 2350–2450 nm ranges. For trembling aspen, differences were evident across most 100 nm intervals, except 2150–2250 nm. Permutational multivariate analysis of variance (PERMANOVA) indicated greater spectral dissimilarity between fungal types in white spruce and trembling aspen, with less pronounced differences in lodgepole pine. Our findings suggest that NIRS can effectively classify fungal-discolored wood in white spruce and trembling aspen within the first year following wildfire. However, its application to lodgepole pine in the same timeframe may be less reliable

Chemical constituents, physical, and mechanical properties of Indonesian sugar palm (Arenga longipes Mogea) trunk

Wood density, chemical characteristics, and mechanical properties in the stem (vertical and horizontal) were studied for the Indonesian sugar palm (Arenga longipes) grown in Sumatera Island in Indonesia. This species is widely used industrially and is widely distributed on the island of North Sumatra. A 15-year-old palm tree was harvested (40 cm diameter at breast height) then sampled at seven heights above the ground (1, 2, 3, 4, 5, 6, and 7 m of trunk height) and at five horizontal positions (4, 8, 12, 16, and 20 cm of radius from the bark) at each height. The sections were evaluated for chemical constituents, density, modulus of rupture (MOR), modulus of elasticity (MOE), tensile strength, and compression strength using British Standard BS 373 (1957). The chemistry of the trunk was also evaluated by gas chromatography-mass spectroscopy (GC-MS), Fourier transform-infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The distribution of chemical constituents of A. longipes stem was as follows: 24.97–39.23% α-cellulose, 68.03–78.04% holocellulose, 23.01–34.44% lignin, and 1.62–3.41% ash content. Density varied from 0.13 to 0.75 g/cm3. Modulus of rupture varied from 10.42 to 143.49 MPa, modulus of elasticity varied from 0.35 to 24.92 GPa, tensile strength ranged from 0.55 to 16.03 GPa, and compressive strength ranged from 0.53 to 6.14 MPa. Hexadecenoic acid and octadecanoic acid were both detected, and the latter compound was most common (97.98% of peak area). The FTIR analysis indicated a hydrophilic tendency in the material, which was attributed to the presence of hydroxyl functional groups in cellulose and lignin. Thermal decomposition occurred at temperatures as high as 402°C, representing an 18% degradation. The horizontal variation within the trunk was highly significant for all traits, while the vertical variation was significant only for density and mechanical properties. A strong correlation was observed between density and mechanical properties. A. longipes has potential as an alternative raw material, capable of supplying the industry with valuable timber substitutes, particularly for material from the outer circumference of the stem

Genetic variations in wood properties of third generation Acacia mangium Willd. progeny tests from Sumatra, Indonesia

Acacia mangium Willd. is a fast-growing tree commonly used in pulp and paper production. Despite extensive planting, there is a need for genetic improvement to enhance wood properties for better pulp output. This study assessed genetic variations in moisture content, pilodyn penetration, specific gravity, fiber length, cell wall thickness, lumen diameter, and cellulose content in a third-generation progeny test of A. mangium in South Sumatra, involving 52 families. Averages for 3-year-old A. mangium were as follows: pilodyn penetration at 11.22 mm, moisture content at 117.18%, specific gravity at 0.44, fiber length at 1.01 mm, and alpha cellulose at 68.03%. Phenotypic variation of wood properties ranged from 3.53% to 19.62%, while genotypic variation was between 1.83% and 9.91%. There was a strong genetic correlation between pilodyn penetration and wood properties (specific gravity, holocellulose, and alpha cellulose) with individual heritability of wood properties estimates (h2i) from 0.09 to 0.37. Significant family differences were found in pilodyn penetration, specific gravity, fiber length, holocellulose, and alpha cellulose, with genetic gains of wood properties between 1.78% and 9.72%

Printability and mechanical properties of wood resin polymer composites manufactured using stereolithography

Wood polymer composites (WPC) fabrication using stereolithography has received little attention. WPC research has been mostly directed to traditional manufacturing methods and fused deposition modeling. Stereolithography offers better print precision, structural accuracy, and ease of production than other 3D printing methods and directly creates the final wood polymer composite. Typically, WPCs fabricated using traditional methods used 40-60% wood in the mixture; however, the highest ratio used with stereolithography has been 10%. Increased wood content reduces costs and creates a product that more closely resembles the mechanical properties of wood. This study focused on increasing the wood flour ratio of WPC printed using stereolithography beyond 10% while studying the factors influencing printability and the mechanical properties of the printed materials. A blend of maple and oak wood flour was combined with methacrylate-based resin at wood levels of 2.5, 5, 7.5, 10, 12.5, 15, and 17.5 wt. % to fabricate the wood polymer composite. The highest ratio of wood flour successfully printed in this study was 17.5 wt.%. This paper discusses the tensile and compressive behaviors of the WPC, as well as the dimensional accuracy of the stereolithography process for higher wood ratio WPC fabrication. The process of fabrication, post processing, success and failure in printing, and characterization of print defects were also studied. Stereolithography can be used to manufacture wood polymer composites in a direct production method at higher wood flour ratios, and improving the capability of the method holds the potential to increase access to a sustainable substitute for conventional wood for various uses

The impact of water exposure on the mechanical properties of a wood-plastic composite

Processed and unprocessed polypropylene samples reinforced with various proportions of pine and beech wood were manufactured using pressure molding and subjected to various mechanical tests. Increasing the percentage of wood particles regardless of the wood species was associated with increased density and hardness of the wood-plastic composite, while tensile strength, deformation at fracture, and elastic limit decreased with increasing particle size. Higher moisture contents were associated with increases in both tensile strength and elastic limit

Particle board production using paper mill waste sludge and European black pine (Pinus nigra A.) wood chips

Paper mills use excessive amounts of water throughout production to produce paper. While mills treat water for reuse, sludge is generated and must be processed as a waste, along with some washing water. In this study, waste sludge from a kraft process mill mixed with up to 40% black pine (Pinus nigra) wood chips was investigated for multi-purpose board production using urea formaldehyde resin and ammonium chloride as a hardener. The panels were pressed at 150°C for 7 minutes between 2.4 MPa and 2.6 MPa. The resulting panels were 18 mm thick, with a density of from 0.69 gr/cm3 to 0.71 g/cm3. Measurements of density, moisture, water absorption, thickness swelling, modulus of rupture, modulus of elasticity and internal bond strength to the surface were carried out on the particle board panels. The results indicated that panels could be used for general purposes

Effect of graphene oxide addition on the characteristics of nanocomposite films made of graphene oxide and nanocellulose obtained from recycled pulp

Films consisting of 6,6,2,2-tetramethylpiperidine-N-oxyl (TEMPO) oxidized cellulose nanofibers (TOCNFs) prepared from recycled pulp and graphene oxide (GO) were produced by the solution molding method. Electrical conductivity titration and FTIR spectra showed that recycled fibers and cellulose nanofibers were successfully oxidized and the number of carboxyl groups increased. Mechanical properties, thermal stability, crystallinity index, and morphological structure of the nanocomposite films of TOCNFs and GO were characterised by tensile strength tests, thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Tensile strength of films made of TOCNFs with 1.5% GO was 61% higher than those without GO, while tensile strength TOCNF films with 3% GO decreased by 2%. The values did not differ statistically from the non-amended TOCNF. Addition of up to 3% GO did not markedly affect thermal stability of nanocomposite films. Recycled pulp had 83% crystallinity, while the crystallinity index of TEMPO-oxidized cellulose nanofibers decreased to 65.5%. SEM observations showed that TOCNFs and small amounts of GO formed nanocomposite films with a homogeneous structure. This research provides an approach for effective utilization of recycled pulp as a feedstock for cellulose nanofibers and TOCNFs/GO nanocomposite films

Spatiotemporal dynamics of termite infestation in urban Araucaria cunninghamii: A case study in Taipei

Termite feeding on the trunk cross-sections of Araucaria cunninghamii in Taipei, Taiwan, was examined using 2D stress wave imaging (FAKOPP system). Six inspections were conducted at 2-month intervals to monitor six trees. 2D cross-sectional stress wave velocity images were created at different heights (30–180 cm) to assess termite feeding damage. Termite damage, quantified as damage ratio (DR, %), ranged from 0% to 55% across different trees and heights, with maximum increases of up to 21% in DR observed over a 2-month period. In the investigated cases, termites primarily fed on the interior of tree trunks. The feeding pattern typically extended longitudinally, then proceeded in a tangential (circular) direction, and finally moved radially. This study identified Coptotermes formosanus as a key termite species involved. Typically, termites prioritized feeding on the earlywood over the latewood. The periods with the highest damage to trunk cross-sections due to termite feeding occurred during seasons with higher temperatures and relative humidity. Damage initially appeared near the heartwood or the boundary between the heartwood and sapwood, gradually expanding into the heartwood. Of the six trees monitored for the full study duration (after one tree was felled for validation), subterranean termite tunneling was observed as the primary pattern in three trees, while aerial swarm invasion patterns were inferred for two trees based on initial damage locations

Compressive behavior of wood I-joist under elevated temperature

Wood composite I-joists are commonly used in residential construction and light commercial buildings, particularly in floor and roof assemblies. These assemblies are often fire-rated, based on building design, to meet specific safety standards. Fire-rated assemblies are constructed using manufacturer-specified materials such as gypsum board and fire-retardant plywood. While I-joists may not be directly exposed to flames, they can still experience significant thermal exposure. This study investigates the effects of elevated temperatures on the compressive strength and modulus of elasticity (MOE) of I-joists, with 90 specimens tested across various temperatures and two exposure durations. Results indicate that significant degradation in mechanical properties occurs around 190°C, with OSB web buckling identified as the primary failure mechanism. A Sigmoidal model was applied to capture the temperature-dependent degradation, revealing critical property decline near 200°C and higher. This research provides insights into the thermal behavior of I-joists, with implications for maintaining structural integrity in high-temperature environments, and highlights the need for further studies on long-term exposure and temperatures above 200°C

Wood quality of farm grown teak (Tectona grandis, Linn.f) under different agroclimatic zones of Tamil Nadu, India

Teak (Tectona grandis) is globally recognized for its exceptional wood quality, making it one of the most sought-after timbers in the world. Teak is visually appealing because of its fine grain and golden-brown hue, and its dimensional stability ensures minimal warping or cracking under various environmental conditions. Wood quality is further influenced by factors such as growth conditions, silvicultural practices, and genetic variability. Although variations in heartwood density and proportion may have an impact on its performance, plantation-grown teak has become a viable substitute for natural forests. Wood fractionation analysis was undertaken by collecting wood samples from all four agroclimatic zones in Tamil Nadu, India of both boundary and block plantations in three different age classes, viz., 5–10, 10–15, and 15–20 years. Wood density, heartwood, sapwood, and bark content were analyzed using species specific allometric equations. Wood density attained a maximum of 0.80 g cm3 in boundary plantations of the Western agroclimatic zone in the 15- to 20-year age class. The same Western zone (WZ) registered the maximum heartwood volume of 0.433 m3 and maximum bark content volume of 0.097 m3 in the same age class. Similarly, maximum sapwood volume in the same age class in the Cauvery Delta zone was 0.141 m3. Trees from the WZ had higher heartwood ratios, suggesting that these trees might more durable