Articles

WOOD RESEARCH Volume 71, Number 3, 2026
Thamer A. Thabet, Normah Awang Besar, Affendy Hassan, Mohamadu Boyie Jalloh, and Nur Fadzlunisaa Wakimin

Investigation of Gamma Radiation Shielding Properties of Acacia Mangium Wood from Sabah, Malaysia

Gamma radiation shielding properties of Acacia mangium wood (ages 3 – 15 years) were investigated at 662 keV (¹³⁷Cs). Mass attenuation coefficients, linear attenuation (µ), and half-thickness were measured; the attenuation properties were discussed include linear attenuation (µ) and mass attenuation (µ/ρ). Additionally, the paper will explore the feasibility of substituting traditional shielding materials, such as concrete and copper, with these tropical wood species for low-energy gamma-ray diagnostic applications. Two mathematical models have been developed to predict wood density based on variations in relaxation length and half-thickness values. The results indicate that the three-year-old Acacia mangium tree has the longest relaxation length at 83.33 cm and the lowest density at 0.43 g/cm³. In contrast, the 15-year-old tree has the shortest relaxation length of 28.56 cm and the highest density at 0.76 g/cm³. Furthermore, the results show that the 3-year-old Acacia mangium tree’s wood has the maximum half-thickness value (57.75 cm), while the fifteen-year-old tree’s wood has the lowest half-thickness value (about 19.85 cm). A good agreement (greater than 85% in most cases) was observed between the measured values and predicted ones. A strong linear correlation was observed between the measured density and the age of the tree (R² = 0.824), as well as between the estimated density and the age of Acacia mangium trees (R² = 0.952). Acacia mangium shows potential as a sustainable gamma shielding material for low-energy applications.

WOOD RESEARCH Volume 71, Number 3, 2026
Crisanto Velázquez-Becerra, Nancy Calderón-Cortés, Mayra Irery Carrillo-Gomez, Alfredo Cortés Muñoz, Nelly Flores-Ramirez, and REBECA DEL CARMEN PEÑA-MONTES

Identification of Fungal Organisms Present in Elements Considered Historical Heritage

In this study, the presence of xylophagous organisms in historical wood present in the temple of Santiago Apostol in Tupátaro, Michoacán, Mexico, was evaluated. Through a visual inspection of three different structural zones in damaged wood of the temple, sampling of various fungal isolates was performed, to be subsequently molecularly identified. Similarly, the temperature and humidity conditions of each site where the samples were taken were recorded, and the laccase and cellulase activities were evaluated for each isolate. The results showed the presence of 14 fungal organisms with well-differentiated morphological characteristics, present in structures such as doors, windows, floors, ceilings, columns, and lintels. Organisms such as Fusarium, Trichoderma, Penicillium, and Aspergillus were found. The temperature and humidity conditions in the temple were found to favor fungal growth in different areas of the structure. The fungi found and identified exhibit enzymatic characteristics to degrade and/or generate aesthetic damage in the colonized wood.

WOOD RESEARCH Volume 71, Number 3, 2026
Igor Džinčić and Ivan Simić

Analysis of the Static Equilibrium Equation of the Oval Mortise and Tenon Joint According to V.N. Mihajlov and V.D. Bekhtejarov

The study analyzes the deviations of the strength values ​​of the oval tenon-mortise joint obtained experimentally in relation to the values ​​obtained by calculating the torsional moment M3, based on the Mihajlov and Bekhtejarov formulas presented by Tkalec and Prekrat (2000). The strength was analyzed by measuring applied load and by calculating ultimate bending moment. In the paper, only the ratio of the tenon side dimensions l:b was varied (l-tenon length; b–tenon height). By analyzing the experimental results, it can be seen that the bending strength and stiffness of the joint increase as the tenon dimensions increase. The results have shown that joint stiffness depends first of all on the tenon width, and the effects of the tenon length are less significant. In the case when the tenon width is greater than its length the Saint–Venant coefficient cannot be applied in the form in which it is given in the analyzed literature. By applying the Saint–Venant coefficient in that form, the calculation results significantly deviate from the results obtained experimentally. The torsional moment equation should be used in its modified form only when the usual dimensions of tenon and mortise are applied.

WOOD RESEARCH Volume 71, Number 3, 2026
CHUN-WON KANG, Young-Woong Lee, HEE-JUN PARK, MASUMI HASEGAWA, Shinya Koga, and HARADHAN KOLYA

Comparative Surface Roughness Evolution of 33 Japanese Hardwoods after Water and Fire-Retardant Treatments Using 3D Optical Profilometry

In this study, we assessed the surface roughness of 33 Japanese hardwood species by 3D optical profilometry (ISO 25178) and examined the influence of water and fire-retardant treatments. The surface roughness on cross, radial, and tangential sections was evaluated using the arithmetic mean height (Sa) parameter. Measurements were performed on untreated samples and repeated on the same spots after water treatment and NF300 fire-retardant treatment. Surface roughness varied widely across species and anatomical sections and tended to decrease with increasing wood density. The surface roughness increased with both treatments compared to the untreated wood. The maximum increase was on tangential surfaces after NF300 treatment, where the mean Sa value increased from 30.14 ± 17.05 μm to 42.05 ± 19.60 μm (39.5%). The statistical analysis showed a significant difference between the untreated and NF300-treated tangential surfaces (p = 0.011).

WOOD RESEARCH Volume 71, Number 3, 2026
Xingyu Shao, MING LI, SAIYIN FANG, TINGTING DENG, KUN DU, JINGGUI WANG, WENTAO XU, and HAO SHI

The Study on the Frequency Response Characteristics of Wood Orthotropy Based on Stress Wave Propagation Direction and Distance

This study investigates the frequency response of Zelkova schneideriana and Pinus sylvestris var. mongholica Litv. along longitudinal, radial, and tangential directions at different propagation distances. Sinusoidal signals from 20 to 200 kHz with 2 kHz intervals were applied using a piezoelectric device, and the responses were recorded by an acoustic emission sensor. Frequency response curves were obtained from the amplitude ratios of response to excitation signals. The results showed that attenuation in the radial direction was lower than that in the longitudinal and tangential directions between 20 and 100 kHz. Both species exhibited stable characteristic response bands around 35, 154, and 188 kHz, which showed good agreement with one-dimensional elastic wave theory, with a minimum relative error of 0.48%. Zelkova schneideriana also exhibited a characteristic frequency near 79 kHz and more stable high-frequency responses.

WOOD RESEARCH Volume 71, Number 3, 2026
EKİM ELÇİN SOYTÜRK, Muratcan Aldemir, and SAIP NAMI KARTAL

Bioremediation of Wood Treated with CCA-C, ACQ, and MCQ Wood Preservatives by Phanerochaete chrysosporium Fungal Strains

This study investigated the bioremediation of wood treated with copper–chromium– arsenic (CCA-C), alkaline copper quat (ACQ), and micronized copper quat (MCQ) using two Phanerochaete chrysosporium fungal strains. Wood flour samples were incubated in fungal liquid cultures over 1 to 10 days. Fungal treatments removed substantially more copper than distilled water controls across all preservative types. Lower preservative loadings yielded copper extraction rates exceeding 90–95% for ACQ and MCQ, whereas higher loadings reduced efficiency. The P. chrysosporium Me strain demonstrated superior performance during later remediation stages. These findings confirm that P. chrysosporium effectively mobilizes copper from soluble and micronized formulations, offering a viable strategy for detoxifying waste wood and enabling resource recovery.

WOOD RESEARCH Volume 71, Number 3, 2026
Bekir Cihad Bal

Evaluation of Some Mechanical Properties of Metal-Mesh Reinforced Poplar Laminated Veneer Lumber

This study aimed to reinforce laminated veneer lumber boards produced with poplar veneers using metal mesh. The metal mesh and poplar veneers were bonded using polyurethane adhesive. A control group (group 1) and three experimental groups were formed. The metal mesh was placed inside the two outermost adhesive layers in group 2, inside the four outermost adhesive layers in group 3, and on the bottom surface (tensile zone) of the board in group 4. The modulus of rupture, modulus of elasticity in bending, splitting strength, and adhesion strength of the produced boards were investigated. According to the data obtained, the modulus of rupture and modulus of elasticity increased in the reinforced groups. Although the reinforcement in one group reached 20%, the other groups had smaller values. Therefore, the reinforcement effect of the metal mesh on the flexural properties remained limited. The splitting strength increased significantly. Compared to the control group, the splitting strength of group 3 increased by approximately 80%. The adhesion strength decreased slightly in the reinforced groups.

WOOD RESEARCH Volume 71, Number 3, 2026
Yuxin Guo, ZIDONG GUO, Hailing Yue, and TIANWEI ZHANG

Influence of Traditional Plaster Layer on the Combustion Performance of Larch and Korean Pine Wood

This study investigated the effects of traditional plastering on the combustion behavior of timber used in historic structures. Larch and Korean pine specimens treated with the traditional one hemp fibre and five plaster layer technique were tested using a Fire Propagation Apparatus (FPA). The plaster layer shortened the time to ignition and promoted fire propagation during the early combustion stage, while markedly reducing the peak heat release rate and toxic gas production and increasing the char yield of the wood specimens. These findings clarify the dual effect of traditional plastering on timber combustion and provide experimental evidence for assessing the fire performance of traditionally plastered components in historic timber buildings.

WOOD RESEARCH Volume 71, Number 3, 2026
Fanny Hidayati, Sugeng Pudjiono, Ratna Adji Hartati, Erlangga Abdillah, Harry Praptoyo, Ananto Triyogo, Gefri Indra Hutabarat, Alfia Dewi Fadwati, Agung Prasetyo, and GANIS LUKMANDARU

Variation of Growth Characteristics and Stress-Wave Velocity of the First Generation Manglietia glauca Families Planted in Indonesia

Growth characteristics, including stem diameter (D), tree height (H), and stem volume (V), and wood property stress-wave velocity (SWV), were measured in 100 families of 7-year-old first-generation Manglietia glauca trees planted in Indonesia. Therefore, this study aimed to evaluate the variation in D, H, V, and SWV among the families and their heritability. An analysis of the correlations, principal components and selection index was also conducted. The presence of significant differences in all measured traits among the families indicate a genetic contribution to traits variation. Low to moderate narrow-sense heritability values were observed across all traits, showing that the genetic enhancement of growth and wood properties in M. glauca is achievable through selective breeding. Moderate to highly significant positive correlations were observed among the growth traits, highlighting their strong interrelationships. D and SWV showed a low significant positive correlation. H and V showed no significant correlation with SWV. Therefore, SWV should be included as selection criterion in M. glauca breeding. PCA and selection index are effectively for identified superior families of growth and strength traits, supporting their selection as candidates for future breeding programs.

WOOD RESEARCH Volume 71, Number 3, 2026
JÁN BRODNIANSKY, SILVIA MARTINKOVIČOVÁ, Jaroslav Sandanus, TOMÁŠ KLAS, JIŘÍ KUNECKÝ, JIŘÍ BLÁHA, and MICHAL KLOIBER

Experimental Investigation of Load Redistribution in a Historic-Type Timber Roof Segment Under Progressive Tie-Beam Weakening

This study examines how progressive loss of tie-beam stiffness redistributes deformation demand and internal force within an experimentally verified historic timber roof segment. A three-frame laboratory model was evaluated by close-range photogrammetry, inductive displacement sensing, post-test bending tests, and finite-element modelling. The measurements revealed clear frame-to-frame stiffness asymmetry, a distinct pre-cut settlement phase under sustained load, and accelerated deformation once the residual tie-beam section was substantially reduced. A refined model using member-specific elastic parameters reproduced the global loading response more accurately than a uniform-stiffness model. The damaged zone could also be represented by an equivalent rotational spring, although the fitted spring values remained response-dependent. The results indicate that lathing acted as a temporary redundancy path after severe weakening and that a nearly hinged residual section was not mechanically equivalent to a fully severed member within the tested configuration.

WOOD RESEARCH Volume 71, Number 3, 2026
QIANHUI HUO, LEI YAN, LILI YU, HUI LI, Jun Li, and SHU-GUANG LI

THE EFFECTS OF INTERFACIAL MODIFICATIONS ON THE PROPERTIES OF BAMBOO FIBER /WASTE TETRA PAK /PLA COMPOSITES

In this study, BF/TP/PLA ternary composite was constructed utilizing bamboo fiber (BF) as the reinforcing phase and waste Tetra Pak (TP) along with polylactic acid (PLA) as the matrix. The effects of different interfacial modification methods on the properties of the composites were systematically investigated. Bamboo fibers were modified using a silane coupling agent (KH570), nano-SiO2, and compatibilizers (MAH-g-PLA, MAH-g-PE). The composites were subsequently fabricated via hot pressing, and their mechanical properties, water absorption, chemical structure, and micromorphology were characterized. The results showed that after KH570 treatment, the flexural modulus and flexural strength of the composites increased by 15% and 32%, respectively. Following the introduction of compatibilizers, the water absorption was further reduced, and the thickness swelling rate was significantly improved. Optimal comprehensive performance was achieved at a nano-SiO2 content of 1 wt%; the flexural modulus reached 2524.1 MPa, exceeding the requirement of Chinese standard LY/T 3275-2021 for outdoor wood-plastic composites (≥2500 MPa), while the water absorption decreased to its lowest value (11.3%). Furthermore, interfacial bonding became more compact.

WOOD RESEARCH Volume 71, Number 3, 2026
SÜHEYLA ESİN KÖKSAL, ORHAN KELLECİ, and YASEMİN ÖZTÜRK

Surface Preparation for Lamination of OSB with Phenol Formaldehyde Film and Melamine Formaldehyde Decorative Paper

This study investigated the lamination of oriented strand board (OSB) surfaces using phenol formaldehyde impregnated polymer film (PF) and melamine formaldehyde impregnated decorative paper (MF). To enhance surface smoothness, OSB panels were sanded and treated with different putty systems, including commercial wood putty, polyvinyl acetate (PVAc), and polyvinyl alcohol (PVA). Ground hazelnut shell and furnace slag particles were incorporated as fillers at a 10% loading level. Results revealed that PF film laminated samples demonstrated significantly superior physical and mechanical performance compared to MF laminated boards. Among all specimens, the sample, prepared exclusively with wood putty and laminated with PF film, achieved the best overall performance, exhibiting the lowest water absorption (WA) and thickness swelling (TS) alongside the highest modulus of rupture (MOR), modulus of elasticity (MOE), abrasion resistance, and surface soundness (SS) values. Although hazelnut shell and furnace slag additions generally reduced putty system performance, their incorporation into PVAc and PVA-based formulations improved certain surface properties.

WOOD RESEARCH Volume 71, Number 3, 2026
SAIP NAMI KARTAL, EKİM ELÇİN SOYTÜRK, YUKO ITO, and WAKAKO OHMURA

Preliminary Evaluation of Copper Leaching from Commercially Available Wood Species in Japan Treated with Copper Azole Wood Preservative

This study examined copper fixation and leaching in wood treated with copper azole (CuAz) and copper sulfate (CuSO₄), emphasizing the effects of wood species and post-treatment conditions. Five Japanese softwoods, including Sugi, Hinoki, and Douglas fir, were assessed under three conditions: unfixed, ambient-fixed, and heat-treated (60°C for 3 days). Copper fixation was defined as the proportion of non-leachable copper remaining after standardized leaching, with release rates measured via leachate analysis. Results showed that post-treatment condition is the dominant factor controlling copper stabilization. Heat treatment significantly enhanced fixation and reduced leaching across all species and preservative types, indicating improved bonding between copper ions and wood components. Ambient fixation was often insufficient. Sugi sapwood showed the highest leaching, while Hinoki heartwood exhibited the greatest retention. Overall, CuAz outperformed CuSO₄, underscoring the importance of formulation in improving copper stability and durability.

WOOD RESEARCH Volume 71, Number 3, 2026
DOAN VAN DUONG and MASUMI HASEGAWA

VARIATION IN BASIC DENSITY AND TRANSVERSE SHRINKAGE AMONG SIX EUCALYPTUS CLONES PLANTED IN VIETNAM

This study examined clonal and radial variation in basic density (BD) and transverse shrinkage among six Eucalyptus clones grown under uniform conditions in north-central Vietnam. A total of 30 ramets were sampled, and 196 small clear specimens were prepared from positions near the pith and the bark. Partial and total shrinkage in tangential (Tn, T) and radial (Rn, R) directions were determined following ISO 13061-13:2017. Basic density (BD) ranged from 0.39 to 0.50 g/cm³ and increased consistently from pith to bark. Tangential shrinkage (Tn: 4.45–5.83%; T: 5.64–6.85%) showed greater variation among clones than radial shrinkage (Rn: 2.95–3.32%; R: 3.89–4.72%). Clone U1427 showed the highest BD while also presenting the lowest shrinkage values, suggesting excellent dimensional stability and considerable potential for utilization in solid wood and lumber production in northern Vietnam.

WOOD RESEARCH Volume 71, Number 3, 2026
FIRDUS HAVERAJ, GERTI XHIXHA, and Dritan Ajdinaj

Short notes. COMPARATIVE STUDY OF THE IMPACT OF THERMAL MODIFICATION PARAMETERS ON THE THERMAL CONDUCTIVITY OF DIFFERENTWOOD COMPOSITE PANELS

This study examined how thermal modification influenced the thermal conductivity of plywood, oriented strand board, and medium-density fiberboard. Samples were exposed to two temperature levels, 130°C and 180°C, for 20 and 40 min, while untreated panels were retained as controls. Measurements were carried out under controlled laboratory conditions using the steady-state hot-box method. The thermal modification consistently reduced thermal conductivity across all materials, which suggests improved insulation properties. The observed reductions varied. OSB exhibited the most significant overall decrease in thermal conductivity, while plywood displayed relative stability; conversely, MDF demonstrated a marked reaction under the more rigorous treatment conditions. The type of material used had the most significant overall statistical effect. The duration of the treatment was more important than the temperature. The interaction between temperature and time did not achieve statistical significance within the parameters of the experiment; conversely, interactions involving material type were significant.

WOOD RESEARCH Volume 71, Number 2, 2026
YUNJING LU, SHILIN XU, and ZIWEI LI

The Study on inhibition and regulation of spruce mannan on enzymatic hydrolysis of cellulose

Mannan is the main hemicellulose in coniferous wood. Spruce mannan was extracted and characterized by FT-IR, SEM and specific surface area test. FT-IR showed it was branched galactoglucomannan; SEM revealed its layered surface and rod-like polymerization units with spherical tops at high magnification; it had small specific surface area and large pore size. Hydrolysis experiments showed spruce mannan inhibited commercial second-generation cellulase (max inhibition rate 22.22%), with inhibition related to hydrolysis time, enzyme dosage and mannan amount. Tween 80 alleviated this inhibition (min inhibition rate 8.69%), promoted β-glucosidase at high concentration (max promotion rate 28.57%), and greatly reduced mannan’s hydrolysis effect (inhibition rate down to 31.82%). This study provides a basis for improving mannan utilization and biomass energy conversion.

WOOD RESEARCH Volume 71, Number 2, 2026
Martina Hladová, JOZEF MARTINKA, PETER RANTUCH, LENKA BLINOVÁ, PETER GOGOLA, IGOR WACHTER, TOMÁŠ ŠTEFKO, and GEORGE I. MANTANIS

In situ synthesis of Mg-Al Layered Double Hydroxides in wood: a novel approach for Enhanced fire performance

This study presents a modified approach for enhancing the fire performance of white poplar wood (Populus alba L.) through the in situ formation of MgAl layered double hydroxides (LDHs) within the wood structure. The treated wood exhibited significantly improved fire properties. The limiting oxygen index (LOI) increased from 19% to 45%, while cone calorimetry results showed reductions of approximately 65% in peak heat release rate (HRR), 58% in total heat release (THR), 80% in maximum average rate of heat emission (MARHE), and 80% in total smoke production (TSP) compared to untreated poplar wood. The enhanced fire performance is attributed to the formation of a protective char layer and the presence of inorganic residues derived from LDH decomposition, which influences the thermal degradation and combustion behaviour of the wood. The results demonstrate that this simple modification approach provides an effective method for improving the fire performance and smoke suppression properties of fast-growing wood species.

WOOD RESEARCH Volume 71, Number 2, 2026
JÁN BRODNIANSKY, SILVIA MARTINKOVIČOVÁ, Jaroslav Sandanus, TOMÁŠ KLAS, JIŘÍ KUNECKÝ, JIŘÍ BLÁHA, and MICHAL KLOIBER

THE EXPERIMENTAL INVESTIGATION OF A MODEL OF A HISTORICAL-TYPE TIMBER ROOF SEGMENT UNDER PROGRESSIVE TIE-BEAM WEAKENING

This paper reports on an experimental study of a model of a historical timber roof segment subjected to progressive weakening of the central tie beam. A three-frame specimen was tested under controlled loading, short-term sustained full load, and sequential cutting of the middle tie beam. Close-range photogrammetry was combined with inductive displacement sensors and conventional control measurements. The study examined the agreement of optical and contact measurements, redistribution of displacement demand to the adjacent frames, and the temporary residual stability provided by lathing after complete failure of the middle tie beam. Across the tie-beam midspans, the mean absolute difference between inductive and paired optical measurements ranged from 0.07 to 0.40 mm, with a maximum point-wise deviation of 1.39 mm. After complete failure, additional settlement of the two intact frames reached 4.28 and 3.97 mm relative to the pre-cut full-load state, indicating longitudinal redistribution through the lathing.

WOOD RESEARCH Volume 71, Number 2, 2026
NIRANJAN KANNANGARA, WASUNDARA INDUMINI, OKDCP MUTHUMALI, CHAMINDA MUTHUMALA, and FAIZ MARIKAR

The Treatability of Selected Local Timber Species with Alkaline Copper Quaternary (ACQ) Preservative: Correlating Wood Anatomy, Physical Properties, and Preservative Performance

This study evaluated the ACQ treatability of 24 local timber species through vacuum pressure impregnation and correlated preservative retention and penetration with physical and anatomical wood properties. Retention ranged widely from 0.478 kg m⁻³ (Bridelia retusa) to 14.980 kg m⁻³ (Cullenia ceylonica and Cupressus macrocarpa). Based on retention and Chrome Azurol S (CAS) penetration assessment, species were classified into four treatability classes. One-way ANOVA confirmed highly significant differences in density (F₂₃,₄₈=199.79; p<0.001), moisture content (F₂₃,₄₈=48.04; p<0.001), and ACQ retention (F₂₃,₄₈=82.75; p<0.001) across species. Pearson correlation analysis revealed a very strong positive relationship between fibre wall thickness and wood density (r=0.955; p<0.05) and a strong negative relationship between fibre lumen diameter and density (r= −0.903; p=0.001), demonstrating that fibre morphology is the dominant determinant of wood density. Neither density (r= −0.411; p=0.163), moisture content (r = 0.005; p = 0.987), total ray area (r=0.097; p=0.789), total vessel area (r= −0.021; p=0.932), fibre wall thickness (r=0.082; p=0.725), nor fibre lumen diameter (r=0.302; p=0.183) produced statistically significant correlations with ACQ retention, indicating that preservative uptake is governed by the combined interactive influence of multiple anatomical and chemical wood properties rather than any single parameter. Cullenia ceylonica, Cupressus macrocarpa, and Ficus amplissima were identified as the most effectively treatable species, classified as very easy to treat (Class 4, retention >10 kg m⁻³) with full penetration exceeding 25 mm. These findings provide a species-specific treatability database for Sri Lankan timber and highlight the need for multi-variable modelling in future preservative research.

WOOD RESEARCH Volume 71, Number 2, 2026
HONGWEI FAN, MIN LI, XINWEI TU, and LIN YANG

RESEARCH PROGRESS IN SILICIFICATION MODIFICATION OF WOOD. REVIEW

Wood is prone to decay, flammability and poor dimensional stability, which restrict its high-value application in furniture manufacturing, architectural decoration and other fields. As an advanced wood modification technology, wood silicification modification can significantly improve wood properties by impregnating silicon-based precursors into the interior of wood and forming SiO2 in situ. This paper reviews the latest research progress of wood silicification modification, elaborates on the structural characteristics of two types of silicon sources (organic and inorganic), sorts out the key points of current mainstream silicification processes, and analyses the improvement effects of wood silicification modification on wood properties such as dimensional stability, decay resistance and flame retardancy. It is proposed that future research is going to focus on the development of green and efficient new technologies and the exploration of organic-inorganic interface regulation mechanisms, aiming to develop multi-functional intelligent silicified wood.