WOOD RESEARCH Volume 70, Number 1, 2025
CHUN-WON KANG, MASUMI HASEGAWA, and HARADHAN KOLYA

EFFECTS OF HOLE PERFORATION AND SURFACE CUTTING ON WOOD ELASTICITY USING ULTRASONIC AND VIBRATION METHODS

This study analyzed how hole perforation and surface cutting affect ultrasonic wave propagation velocity and resonant frequency in wood. While non-destructive evaluation techniques for wood elasticity are well-established, the specific influence of defects like holes and orthogonal cuts on wave behavior remains underexplored. This study aimed to fill this gap by assessing how these defects influence wave behavior and providing new insights into their impact on wood’s mechanical properties. Four softwood species and seven hardwood species were analyzed. In hardwood specimens, ultrasonic propagation velocity and resonant frequency were measured under increasing levels of hole perforation (9, 27, and 45 holes). In contrast, the effects of one and two orthogonal surface cuts were examined in softwood specimens. The results revealed that the ultrasonic propagation velocity decreased noticeably with an increasing number of holes. Meanwhile, resonant frequency exhibited only a slight decrease. In contrast, softwoods displayed minimal changes in ultrasonic velocity but notable reductions in resonant frequency due to surface cutting. This study highlights the differences in continuous wave propagation pathways associated with the two defect types and estimation methods, offering novel insights into wood evaluation techniques

WOOD RESEARCH Volume 70, Number 1, 2025
MATEUSZ SZAR, JAROSŁAW KOZAK, WOJCIECH SPISAK, TIINA TÖRMÄNEN, and ANDRZEJ CHLEBICKI

IMPREGNATED WILLOW WOOD CHIPS (SALIX VIMINALIS L.): A NOVEL SOIL AMENDMENT FOR ENHANCING SOIL QUALITY

This study introduces a novel method of treating willow chips (Salix viminalis L.) by impregnating them with a solution of conventional mineral fertilizers. Modified willow wood chips have the potential to utilize as an innovative soil amendment and offer benefits for agriculture, horticulture and forestry to improve soil water retention capacity, soil fertility and structure. Experimental results indicate the feasibility of developing a product with nitrogen (N) levels from a minimum of 2%, phosphorus (P) levels exceeding 0.5%, potassium (K) levels exceeding 1.5%, and an organic matter content over 90% of the dry weight

WOOD RESEARCH Volume 70, Number 1, 2025
JORGE GARATE-QUISPE, MAURO VELA-DA-FONSECA, PERCY ZEVALLOS-POLLITO, JAIME FERNANDO TUESTA VASQUEZ, TELESFORO VASQUEZ ZAVALETA, ANDREA AUCAHUASI-ALMIDON, REMBRANDT CANAHUIRE-ROBLES, and GABRIEL ALARCON-AGUIRRE

CHARACTERIZING GROWTH, MACROSCOPIC AND MICROSCOPIC ANATOMICAL FEATURES OF OCHROMA PYRAMIDALEFROM SECONDARY FORESTS, PERUVIAN AMAZON

The study aimed to characterize the radial growth,macroscopic and microscopic anatomical features in wood, and determine the rotation time of Ochroma pyramidale in secondary forests of the southeast Peruvian Amazon. We harvested 13 whole slabs of wood from trees of O. pyramidale. A total of 32 radii and 9 cross sections were dated and crosschecked. The study demonstrates that annual growth rings of O. pyramidale have a common growth signal in secondary forests. This species has potential for analyzing the effects of climate on radial growth. Growth rings are visible to the naked eye and demarcated by a dark-colored tangential fibre arrangement. O. pyramidale showed a high growth rate, mean diameter increment was 1.1 cm/year. The results of the selected model suggest that the rotation time or technical cutting shift of maximum production for O. pyramidale is at 12 years. However, considering the demand for softwood, we recommend that six years of rotation

WOOD RESEARCH Volume 70, Number 1, 2025
YINLUAN QIN, XIAOLI PANG, LONGHAI CHEN, XIAORONG ZHENG, WENBANG WEI, DAJUN LONG, and JING TANG

ENHANCED PERMEABILITY OF EUCALYPTUS CLOEZIANA BASED ON NAOH/Na2SO3 AND H2O2 TREATMENTS

The synergistic effects of NaOH/Na2SO3 and H2O2 treatments on enhancing the permeability of Eucalyptus cloeziana wood were investigated. Treated and untreated specimens were analysed for pore size, microstructure, and chemical composition. The results showed that the treated wood had significantly increased average pore sizes and was characterised by cracks in the wood pits. Additionally, the contents of hemicelluloses and lignin structural components decreased, enhancing permeability. The treated wood showed a 1.2- to 1.8-fold water absorption rate higher than untreated wood. These changes result from the reaction of NaOH/Na2SO3 and H2O2 with wood

WOOD RESEARCH Volume 70, Number 1, 2025
OSMAN ÇAMLIBEL and MURAT AYDIN

INFLUENCE OF PARAFFIN ON MDF PROPERTIES AT INDUSTRIAL SCALE

In this study, the effect of paraffin addition on the modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), water absorption (WA), and thickness swelling (TS) properties of fiberboard by density variations was evaluated. Higher mechanical properties were calculated for the paraffin-free board. MOR and MOE of the boards decreased with the increase in density, but not linearly; indeed, fluctuations were observed. Conversely, IB values were increased with the increase in density. The adverse effect of paraffin on the mechanical properties was almost eliminated with the increase in density, particularly for the 750 kg/m³ density profile, except for IB. The WA performance of the boards was significantly increased (58.8%) with the increase in density. Furthermore, advances with the density increase were uplifted by paraffin addition. However, when water repellency properties and advances in WA were taken into consideration, paraffin addition caused the opposite behavior for TS, but around 5.1% decrease in TS was achieved for the 750 kg/m³ density profile

WOOD RESEARCH Volume 70, Number 1, 2025
DOAN VAN DUONG, VAN HUNG HOANG, MASUMI HASEGAWA, and EVGENII SHARAPOV

THE INFLUENCE OF TREE AGE AND RADIAL POSITION ON THE STRESS-WAVE VELOCITY AND TIMBER PROPERTIES OF PINUS MASSONIANA LAMB. PLANTED IN VIETNAM

The main objective of this study is to investigate the influence of tree age and radial position on the structural properties, asair-dry density (AD), modulus of rupture (MOR), modulus of elasticity (MOE) and the stress-wave velocity measured on small specimens (SWVS). Results of analysis showed a highly significant effect of age and radial position on the SWVS, AD, MOR, and MOE. Stress-wave velocity and wood property traits tend to increase with increasing tree age. The SWVS and selected wood properties near the pith were significantly lower than those near the bark. Mean MOR and MOE of the timber had significantly (P<0.001) relationships with SWVS (r = 0.75 and 0.91, respectively), although in the case of MOR a model based on AD alone is slightly better (r = 0.79). There were also significant relationships of acoustic velocity measured in standing trees (SWVT) with mechanical properties measured destructively in small specimens implying that stress-wave method has a good potential for measuring static bending properties of P. massonianaplanted in Vietnam

WOOD RESEARCH Volume 70, Number 1, 2025
QIANHUI HUO, LEI YAN, XINJIE ZHOU, LILI YU, LIHUA HE, XIAO WANG, HUI LI, and LONGZE AN

WEATHERABILITY OF BAMBOO/PPC COMPOSITES MODIFIED WITH IPBC/DDAC AND UV1130

In this study, a compound anti-mold agent IPBC/DDAC and an ultraviolet absorber UV1130 were used to enhance the weatherability of bamboo/polypropylene carbonate (PPC) composites exposed outdoors. The samples were evaluated by mechanical test, surface color difference analysis, anti-ageing test and mold resistance test. The results indicated that the appropriate addition of IPBC/DDAC and UV1130 effectively mitigated the decline in tensile strength and flexural strength caused by changes in environmental factors; however, their impact on the variation in impact strength was not as significant. At the same level of IPBC/DDAC modification, the higher contents of the UV1130 introduction into the composites, the better surface color stability could be obtained. The introduction of appropriate amount of IPBC/DDAC and UV1130 can effectively improve the mold resistance, water vapor and thermal resistance of bamboo/PPC composite, in which the water vapor resistant level could be up to Grade 5, and no obvious cracks or bubbling were observed on the surface of the composites; the anti-mold efficiency of the composites could be above 90%

WOOD RESEARCH Volume 70, Number 1, 2025
LEI YAN, QIANHUI HUO, XINJIE ZHOU, HAN YU, LILI YU, LIHUA HE, XIAO WANG, HUI LI, and DEZHI ZHOU

EFFECTS OF WASTE POLYETHYLENE ON THE PROPERTIES OF BAMBOO/POLYPROPYLENE CARBONATE COMPOSITES

Bamboo-plastic composites were made by bamboo fibers (BF), polypropylene carbonate (PPC) and waste polyethylene (PE), modified with 3-iodo-2-propargyl butyl carbamate/didecyldimethyl ammonium chloride (IPBC/DDAC) as fungicides and UV1130 as ultraviolet absorbent to prolong their service life for outdoor application, in which 10%, 20%, 30%, 40% and 50% of PPC were replaced by waste PE, respectively to reduce their cost. The modified composites were characterized and analyzed by mechanical properties test, surface color difference analysis, and mold resistance test. The results showed that the tensile strength, bending strength and impact strength of BF/PPC/waste PE composites would decrease as the waste PE content increased, and only when the waste PE content was not higher than 20%, the mechanical properties could meet the application requirements for indoors and outdoors. The introduction of IPBC/DDAC and UV1130 could take positive effects on the mechanical properties, surface color stability and mold resistance of BF/PPC composites, while the tensile strength, bending strength and impact strength of BF/PPC/PE composites were 2.36%, 1.85%, and 1.67% lower than the modified BF/PPC composites, as well as the values of ∆L*, ∆a*, and ∆b* of the composites were lower , and the value of ∆E was higher than the BF/PPC modified composites after three months of outdoor exposure. The efficacy levels of the modified BF/PPC and BF/PPC/waste PE composites could be increased to 98.8% and 56.75%, respectively, due to the excellent mold resistance of the combined antifungal agents of IPBC/DDAC

WOOD RESEARCH Volume 70, Number 1, 2025
GÁBOR ORBÁN and ANTAL KÁNNÁR

ASSESSING THE DISMANTLED GLUED-LAMINATED STRUCTURE OF A NATATORIUM AFTER 35 YEARS IN SERVICE

The article describes the results of the investigation of the load-bearing capacity of the recently dismantled roof structure of the Csik Ferenc Natatorium in Sopron, Hungary, after 35 years of service. The investigation was aimed at measuring the tensile strength perpendicular to the grain, shear strength and global bending strength of the beams and comparing it to the appropriate design stress values. The results showed that the tensile and shear strength of the beams fulfilled the criteria of the Eurocode 5 standard. The bending strength of the full size beam meets the Eurocode5 design strength requirements for strength class GL 36h. The bending MOE does not fulfil the criterion for this strength class, but is higher than the mean value of a GL 24h beam

WOOD RESEARCH Volume 70, Number 1, 2025
LI LILI, LUO ZHIYING, LIU WENWEN, LIU DE, WANG XIMING, and YU JIANFANG

THE EFFECT OF COMBINED FLAME RETARDANTS ON THE PHYSICAL AND MECHANICAL PROPERTIES OF MONGOLIAN PINE

To enhance the flame-retardant properties and physical-mechanical performance of wood, this experiment selected Mongolian pine as the material and employed a vacuum-pressure impregnation method, with different ratios of borax and ammonium polyphosphate (BO:APP) (1:1, 2:1, 1:2) applied and compared with untreated wood (BCW). The treated and untreated Mongolian pine samples were analyzed using scanning electron microscopy (SEM), a universal mechanical testing machine, a limiting oxygen index (LOI) tester, and thermogravimetric analysis (TG) to assess microstructure, weight gain rates, density, physical-mechanical properties, flame retardancy, and thermal stability. Results indicate that the flame retardants were uniformly dispersed within the wood’s pores, achieving excellent impregnation. The weight gain rates and density of the treated wood improved when the weight ratio of borax to ammonium polyphosphate was in ratio1:1 (BO-1:APP-1 group).The weight gain rates was 10.36% and a density of 0.632 cm³/g and the MOE and MOR reached 12,076 MPa and 116.3 MPa, respectively, representing increases of 26.5% and 16.7% compared to untreated samples. The oxygen index of the BCW group was 23.1%, while that of the BO-1:APP-1 group was 42.5%, reflecting an 84% improvement over the BCW group. The thermal decomposition temperature of the treated samples decreased by 50°C, with the BCW group’s char yield at 11.35%, whereas the char yield for treated samples exceeded 20%, reaching 37.44% for the BO-1:APP-1 group, marking a 230% increase compared to the BCW group

WOOD RESEARCH Volume 70, Number 1, 2025
Vladimír Mózer, LUKÁŠ VELEBIL, and ANDREA SMETANOVÁ

INVESTIGATION OF CLT PANEL DEGRADATION DURING HEATING AND COOLING PHASES OF FIRE

The research presented in this paper investigates the behavior of Cross-laminated timber (CLT) under fire exposure during the heating and cooling phases. A sample CLT panel was exposed to a 60 min heating phase as per the ISO 834 standard time-temperature curve, following which it was removed from the furnace and left to cool at ambient temperature. Due to char formation and availability of oxygen during the intended cooling phase, the intensity glowing combustion was growing and resulted in increasing temperatures and even flaming combustion in its latter stages. The char layer thickness doubled during the intended cooling phase under the experimental conditions. Temperature profiles measured parallel and perpendicular to isotherms indicated significant underestimations associated with the perpendicular orientation. The study highlights the need for consideration and further investigation of the cooling phase and its impact on structural design and fire investigation

WOOD RESEARCH Volume 70, Number 1, 2025
JINGGUI WANG, MING LI, SAIYIN FANG, TINGTING DENG, ER ZHUANG ZHAI, CHUMIN CHEN, and KEFEI CHEN

RESEARCH ON WOOD DAMAGE FRACTURE CHARACTERISTICS BASED ON ACOUSTIC EMISSION RA-AF VALUE AND ENERGY CONCENTRATION

To study the acoustic emission (AE) characteristics and fracture properties of wood at different stress stages, three-point bending tests and real-time AE monitoring were carried out on Zelkova schneideriana and Pinus sylvestris var. in this paper. Different stress stages were classified according to AE ringing counts-cumulative AE ringing counts-load curves, damage modes of wood at different stages were identified based on distribution characteristics of RA-AF data, and fracture behavior of wood was predicted by energy concentration k. Results show that distribution characteristics of AE RA-AF data can characterize the types of cracks generated in each stress stage of wood. The crack modes generated by both specimens during three-point bending loading are tension shear composite cracks, and the proportion of tensile cracks is significantly higher than that of shear cracks, but during the elastic-plastic stage, Zelkova schneideriana specimens will produce a large number of shear cracks, whereas Pinus sylvestris var. specimens have predominantly tensile cracks, with only a small number of shear cracks produced before and after fracture. The sudden change in the energy concentration k curve between elastic-plastic deformation stage and fracture stage can be used as a precursor of damage for both specimens under three-point bending test conditions

WOOD RESEARCH Volume 70, Number 1, 2025
NUR SAFITRI, AUDREY KINANTI, IMAM WAHYUDI, and ANDI DETTI YUNIANTI

COMPARISON OF FIBER QUALITY AND ANATOMICAL STRUCTURES OF ACACIA MANGIUM FROM BREEDING ACTIVITIES

This study aimed to analyze the effect of a tree breeding program on the fiber quality and anatomical structure of 10-year-old Acacia mangium wood. There are three trees in each breeding generation, namely the first generation (F0) and the second generation (F1). The results showed the average fiber dimensions of all populations were as follows: First generation has 966.05 µm length, 19.84 µm diameter, and 3.78 µm cell wall thickness, while Second generation has 1046.23 µm fiber length, 20.23 µm fiber diameter, and 3.56 µm cell wall thickness. The genetic improvement treatment showed significant improvement in the fiber dimension. According to the quality classification grade for pulp and paper raw materials, all populations belong to quality class II. Based on the list of the International Association of Wood Anatomists (IAWA), it can be ascertained that the wood anatomical structures of all populations showed no microscopic differences

WOOD RESEARCH Volume 70, Number 1, 2025
JUAN DOMINGUEZ, INGRID CASSANA, and LEIF PORTAL

RELATIONSHIPS BETWEEN WOOD ANATOMY, PHYSICAL PROPERTIES AND COLORIMETRY IN TRICHILIA DAZAE T.D. PENN.: AN ENDEMIC SPECIES OF THE HUMID MONTANE FOREST OF PERU

Trichilia dazae, an endemic tree from the humid montane forests of the Peruvian Andes, plays an important ecological and potential economic role. Despite this, there is a significant gap in the characterization of its wood. This study aimed to analyze the anatomical, physical, and colorimetric properties of T. dazae wood to assess its technological potential and promote its sustainable use. Samples from three trees in the San Carlos district, Bongará, Peru, were collected. Anatomical description and physical properties were evaluated using international standards, while colorimetric analysis was conducted using the CIE Lab* system. The results showed distinct anatomical characteristics, such as diffuse porosity and heterocellular rays, associated with a basic density of 0.64 g/cm³. Significant correlations were found between basic density and anatomical features, suggesting a balance between mechanical strength and hydraulic conductivity. These findings emphasize the species’ value for both structural and decorative applications

WOOD RESEARCH Volume 70, Number 1, 2025
RICARDO DE CARVALHO BITTENCOURT, MATHIAS TEIXEIRA MARÇAL, STÉPHANI CAROLINE DE LANA ARÊDES, GABRIEL MARTINS DAVID, TIAGO GUIMARÃES, GABRIEL DE CASTRO BAIAO BRUMANO, and MARCELO MOREIRA DA COSTA

Short notes. Prolonged Impregnation of Bamboo chipsin Pre-Hydrolysis kraft pulping for Dissolving pulp production

The aim of the article was to compare the feasibility of different impregnation processes of chips and production of soluble bamboo pulp by the pre-hydrolysis kraft (PHK) method.The chips made of Bambusa vulgariswere subjected to prolonged or conventional impregnation with white liquor, followed by the pre-hydrolysis, neutralization, kraft cooking and washing stages. The brown pulp was subjected to a bleaching process using an elemental chlorine-free (ECF) sequence. The results showed that prolonged impregnation provided greater delignification and lower reagent consumption than conventional impregnation. The pulp produced from prolonged impregnation with 14% effective alkali (EA) presented the best properties for dissolution, with intrinsic viscosity of 437 dm3/kg, brightness of 88% ISO, xylan content of 3.48% and glycan content of 94.5%. TAC consumption was low for both impregnations. The study concluded that Bambusa vulgaris can be used in the production of dissolving pulp, mainly for viscose grade