WOOD RESEARCH Volume 67, Number 4, 2022
Song Chen, Xiyang Zhao, and Su Chen

Identification of the cell wall synthesis genes in Betula Pendula

This study aims to provide information on Betula pendula cell wall synthesis genes regarding their potential physiological roles and the molecular mechanism associated. Here we identified 46 gene models in 7 gene families that encode cellulose synthase and related enzymes of B. pendula, and the transcript abundance of these genes in xylem, root, leaf, and flower tissues also be determined. Based on these RNA-seq data, we have identified 8 genes that most likely participate in cell wall synthesis, which include 3 cellulose synthase genes and 5 cellulose synthase-like genes. In parallel, a gene co-expression network was also constructed based on transcriptome sequencing. These analyses will help decipher the genetic information of B. pendula cell wall synthesis genes and alter its wood structure on the cellular level.

WOOD RESEARCH Volume 67, Number 4, 2022
DUŠAN JOKANOVIĆ, Tatjana Ćirković-Mitrović, VESNA NIKOLIĆ JOKANOVIĆ, and Radoslav Lozjanin

Variability of wood fibres of mature pedunculate oak in flooded and non-flooded area

The paper deals with anatomical characteristics of wood fibres of Quercus robur L. Fiber length, double-cell wall thickness and fiber lumen diameter were analysed from samples in flooded and non-flooded area along Sava river in Serbia. All anatomical elements were measured from pith to bark in order to establish variation with cambial age, not only between researched sites, but also between individuals within each locality. In this study, there was no statistically significant difference only for mean values of fiber length between individual trees at non-flooded area, and in fiber lumen diameter at flooded area. Increasing of mean values of observed anatomical parameters with cambial age is valid for flooded area (MU „Grabovako-vitojevačko ostrvo 20e“), while for another locality (MU “Blata-Malovanci”) it is the case just for double-cell wall thickness. Mean values of all analysed anatomical elements are bigger in flooded area and this could be a consequence of more suitable ecological conditions for Quercus robur L. development present in this locality. Obtained variations show nonhomogeneous wood fibre features at both localities.

WOOD RESEARCH Volume 67, Number 4, 2022
Yan Yang, Xiaoqian Zhang, Qian Xu, Peiyang Wang, Shilong Jiang, Yan Min, Wenye Sun, Bin Li, Yulong Fan, and Shuang Yang

Evaluation of the decay levels of wooden components in arcade buildings in the ancient town Chikan via polarized light, fluorescence and FTIR spectra

In order to classify the decay levels of Chinese fir (Cunninghamia lanceolata) wood components in arcade buildings in the ancient town Chikan and to provide basic data for future protection measures, the extent of decay of the samples was determined via polarized light, fluorescence, and Fourier-transform infrared spectroscopy. The results were as follows: (1) The total birefringence brightness of crystalline cellulose and the green fluorescence brightness of the lignins were reduced to different degrees in almost all samples. (2) The absorption peaks at 1731 cm-1 representing hemicellulose and at 891 cm-1 representing cellulose in all samples disappeared. The absorption peak heights at 1370 cm-1, 1159 cm-1 and 1058 cm-1 which represents holocellulose, and at 1508 cm-1, 1424 cm-1, and 1262 cm-1 which represents lignin decreased to varying degrees. (3) From the analysis, the decay level of wooden components in arcade buildings was divided into three classes, i.e., Level I (severe decay), Level II (moderate decay), and Level III (mild decay).

WOOD RESEARCH Volume 67, Number 4, 2022
EUN-SUK JANG and CHUN-WON KANG

Investigation on the Malaysian Duabanga moluccana cross sections as sound absorbing functional materials

This study focused on Duabanga moluccana, which is a fast-growing tropical tree native to Southeast Asia. Duabanga moluccana cross sectional specimens were analyzed to gas permeability, pore size, and open-pore porosity and also measured its sound absorption coefficients with an impedance tube. Duabanga moluccana showed a larger pore size and greater open-pore porosity than other hardwood species, and its sound absorbing performance was superior to that of the gypsum board currently used as a commercial ceiling material. Although this was a laboratory-scale investigation, we demonstrate that Duabanga moluccana cross sections have potential as a natural sound absorbing functional building material.

WOOD RESEARCH Volume 67, Number 4, 2022
Xiaoyan Zhang and Guangjie Zhao

Yeast cultivation for single-cell protein production using the carbohydrate hydrolysate of steam-exploded eucalyptus wood

This study was aimed at producing single-cell (SCP) protein from the carbohydrate hydrolysate of steam-exploded eucalyptus (Eucalyptus urophylla) wood. Two yeast strains including Saccharomyces cerevisiae and Candida utilis 2.587 were used for batch fermentation. Results showed that the total reducing sugars (TRS), glucose and xylose in hydrolysate had concentrations of 17.52, 10.71, and 4.30 g•L-1, respectively. During fermentation, yeast strains of S. cerevisiae and C. utilis 2.587 used monosaccharides sequentially, and secondary growth occurred. The yeast biomass contained 43.59% crude protein and was rich in all essential amino acids such as lysine, leucine, and valine. Total amino acid reached 401.45 g•kg-1, and corresponded with the standard recommended by the Food and Agriculture Organization of the United Nations for amino acids, except sulfur-containing amino acids.

WOOD RESEARCH Volume 67, Number 4, 2022
SAIYIN FANG, MING LI, TINGTING DENG, and Kun Du

Study on the time-frequency characteristics and propagation law of acoustic emission longitudinal waves in wood grain direction

To study the propagation law of acoustic emission (AE) longitudinal waves in wood, the relationship among wave velocity, standing wave fundamental frequency and Young’s modulus of elasticity was studied, and the energy decay model of AE longitudinal waves along the grain direction was established. Firstly, the propagation velocity of the longitudinal wave was calculated using the time-difference method. Then, the relationship between the wave velocity and Young’s modulus of elasticity was analyzed and the method of calculating the longitudinal wave velocity using the fundamental frequency was proposed. Finally, using different levels’ pulse strings as AE sources, the attenuation law of AE signal energy with distance was studied. The results show that the longitudinal wave velocity can be estimated more accurately by using the standing wave fundamental frequency. The influence of Poisson’s ratio needs to be considered when calculating the Young’s modulus of elasticity by using the longitudinal wave velocity.

WOOD RESEARCH Volume 67, Number 4, 2022
Mario Núñez-Decap, Gustavo Pérez-Soto, Alexander Opazo-Vega, Boris Moya-Rojas, and Marcela Vidal-Vega

Study of wood adhesives on the bonding properties in solid and hollow glulam beams of Pinus radiata

The aim of this research was study of polyurethane (PUR), isocyanate polymer emulsions (EPI) and melamine-urea-formaldehyde (MUF) adhesives, on the bonding properties of solid and hollow glulam beams of Pinus radiata. The thermomechanical analysis (DMA) of the adhesives was carried out to evaluate their stiffness and reactivity. Glulam beams were evaluated by a bending test. The quality of the bonding was evaluated by resistance to shear and delamination. The morphology of the bonding was studied by microscopy. The DMA study showed that the MUF adhesive had the highest level of stiffness and reactivity. The results of the bending test showed that the highest modulus of rupture results were obtained in solid and hollow laminated beams with MUF adhesive, achieving increases of 30% over the PUR adhesive. The lowest delamination results were obtained in solid glulam beams with MUF and EPI adhesives, while the highest results were 32% and 47% for the PUR adhesive. Finally, glulam beams manufactured with MUF adhesive presented the best performance and results.

WOOD RESEARCH Volume 67, Number 4, 2022
Eliška Hřebenářová and František Wald

Comparison of mechanical properties of the eldest larch wood construction with oak wood and spruce wood

The paper discusses mechanical properties of timber for structures – most frequently used spruce wood, historically used oak wood and rarely mentioned larch wood. The main focus is on larch wood extracted from the ceiling of an immovable cultural monument from the 17th century – the determination of its age, its historical importance and mechanical properties. Mechanical properties were obtained by the standard tests in compression parallel and perpendicular to the fibres and in bending. The results of tests are compared to the mechanical properties of oak wood, of commonly used spruce wood and of recently felled larch wood.

WOOD RESEARCH Volume 67, Number 4, 2022
Isabella Silva Menezes, IURI FAZOLIN FRAGA, Matheus Henrique Morato De Moraes, ANDRÉ LUIS CHRISTOFORO, Fernando Júnior Resende Mascarenhas, Raquel Schmitt Cavalheiro, Francisco Antonio Rocco Lahr, Eduardo Chahud, Luiz Antônio Melgaço Nunes Branco, and Herisson Ferreira dos Santos

Empirical analysis of roof slope influence on material consumption in timber howe-type trusses

In Brazil, some tile manufacturers have proposed a 10% (5.5°) slope between chords to minimize timber consumption. However, after simulating 21 slopes from 7% (4°) to 27% (15°), it was discovered that the axial strengths are inversely proportional to the slope, creating overly large dimensions for the bars competing for support. The results were obtained using software developed following the guidelines specified in the revised version of the ABNT NBR 7190 (2022) standard. Finally, it was found that the minimum slope until no reinforcement is needed for the string bars is 16% (9°).

WOOD RESEARCH Volume 67, Number 4, 2022
Sefa Durmaz and Özlem Özgenç

The changes in the surface of flat pressed wood-plastic composites exposed to artificial weathering

In this study, the wood flour content’s effect on the weathering performance of flat pressed WPC was investigated. The high density polyethylene was reinforced with four different wood flour content (10%, 30%, 50%, 70%). The weathering performance of WPC was determined by the 400 h of artificial weathering test. According to the results, the color change is inevitable as long as the wood flour is used as filler. Surprisingly, the highest color change was obtained from WPC containing 30% WF, contrary to 70% of wood flour. Similarly, the whiteness of the surface of WPC increased with exposure time. The photooxidation resulted in the chain scission and shorter molecules, which were observed by ATR-FTIR analysis. The changes in the intensity of characteristic polymer (2914 cm-1 and 2846 cm-1) and wood peaks (1510 cm-1 and 1027 cm-1) exhibited the photodegradation on WPCs’ surface, which resulted in color change. Moreover, the light microscopy investigation showed surface degradation. The extensive weathering conditions caused surface cracks and surface roughness. The visual appearance of WPCs also demonstrated how to change the surface character of WPC during the 400 h of artificial weathering. In conclusion, the increase in the wood content increased the intensity of degradation.

WOOD RESEARCH Volume 67, Number 4, 2022
Song Xiaozhou, Liu Guorui, Feng Xuechun, and Zhang Li

Preparation and properties of agglomerated cork panels bound with chitosan binder

In this paper, acidified chitosan was used as an adhesive to prepare aldehyde-free, environmentally-friendly agglomerated cork panels by hot-pressing. After preparation, the physical, mechanical, and the finishing properties of the chitosan-glued agglomerated cork panels were investigated. The optimal mass ratio of acetic acid solution (1 wt.%) to chitosan was determined to be 30:1. The resulting hot-pressed agglomerated cork panels, which featured a density of 0.55 g.cm-3 and a thickness of 4 mm, exhibited a tensile strength of 1.70 MPa and a thermal conductivity of 0.11 W.m-1•K-1. The agglomerated cork panels coated with the oil-based polyurethane and water-based, acrylic-modified polyurethane paints exhibited significantly lower lightness and higher glossiness. The total color differences (ΔE*) of both agglomerated cork panels increased before and after finishing. The oil-based polyurethane paint coating exhibited high adhesion of paint film, reaching a level-0 adhesion, while the water-based, acrylic-modified polyurethane paint coating achieved a level-1 adhesion. The abrasion resistance results showed that the substrates of cork agglomerates coated two types of paint did not expose after undergoing abrasion for 100 revolutions at the turntable speed of 60 rpm.

WOOD RESEARCH Volume 67, Number 4, 2022
Kang Zhou, Zirui Ren, Chen Shuosun, and Bin Na

The study on glue-applying methods and hot-pressing technology of parallel strand lumber

Parallel strand lumber (PSL) was manufactured from the veneer strand cut from the poplar broken veneers of the plywood enterprises, by analyzing the influence of the size of veneer strands, the glue concentration and glue-applying time on the glue-absorbing amount of veneer strands, the influence of three different glue-applying was, hot-pressing time and temperature on the physical and mechanical properties of PSL was reviewed and the hot-pressing technology was optimized. The experiment results showed that the size of the veneer strands have not notable influence on the gluing-absorbing amount, and mainly affect the homogeneity and appearance quality of the product. The glue concentration is one main factor to affect the glue-absorbing amount of veneer strands and PF resin of 30% concentration was chosen. The glue-applying way is the main factor to affect the mechanical property of PSL. The hot-pressing time and temperature have significant influence on physical and mechanical properties of PSL. Comprehensively considering, the physical and mechanical properties and homogeneity of products are better using the veneer strands with 100 mm length, the glue-spraying way and hot-pressing technology with the time 35 min and the temperature of 150°C.

WOOD RESEARCH Volume 67, Number 4, 2022
Juraj Gigac, Mária Fišerová, and Radko Tiňo

Effect of paperboard surface modifications on electrical conductivity of printed UHF RFID antennas

The effect of surface roughness and water contact angle of commercial paperboard before and after surface modification by calendering, coating and calendering and plasma treatment on the functionality of UHF RFID antennas printed with thermal transfer aluminum ribbon was evaluated. A hydrophilic surface was created by coating or plasma treatment, which improved the wettability of the paperboard surface, the spreading of the thermoplastic tie layer and the adhesion of the conductive aluminum layer. A new paper product was created with permanent surface wettability by coating, without the need for plasma treatment before printing. The plasma treatment provided time-limited wettability, needed only during printing, and made it possible to restore the original hydrophobic surface of the paperboard. In addition to the meaning of these surface modifications, the importance and need to reduce the surface roughness was confirmed, as the higher surface roughness of the paperboard limited the effect of the plasma treatment in terms of its printability and the functionality of the printed aluminum antenna. The printability of the paperboard and the functionality of the printed antennas were evaluated using electrical conductivity. The electrical conductivities of the dipole and inductor loop of the UHF RFID antennas printed on modified paperboards varied depending on the antenna design.

WOOD RESEARCH Volume 67, Number 4, 2022
Zihao Liu, Sulan Zhang, Xiaojun Jia, and Jun Yang

A novel wood feature extraction method based on improved blocked higher-order local auto-correlation

Traditionally, HLAC (Higher-order Local Auto-Correlation) algorithm was used to extract texture features of wood images. However, heavy memory consumption and complexity of high-order mask pattern were common in HLAC. A novel feature extraction strategy based on improved blocked higher-order local auto-correlation (IBHLAC) is proposed to circumvent these problems. Initially, sequences of the whole wood image frames, which are the grayscale treatment, were being divided into series of subdivisions vertically and horizontally. Additionally, to enhance auto-correlation ability of the proposed method, different high-order patterns of masks were rebuilt based on zero-order mask by introducing the morphology and affine transformation. Finally, time-consumption and memory occupation of related four methods were compared. Experiment results indicated IBHLAC costs less time and fewer memory consumption on the wood texture database compared with other methods, which reveal that IBHLAC is efficient.

WOOD RESEARCH Volume 67, Number 4, 2022
Oussama Chauiyakh, Samar Aarabi, Oumaima Ninich, Elmostafa El Fahime, Fatiha Bentata, and Aziz Et-Tahir

Short notes: First report of the lignivorous fungus Pleurostoma richardsiae in Cedrus atlantica M. in Morocco

Our study is interested in isolating fungi from the wood parts of cedar trunks withered and identifying these lignivorous fungi. A sample was isolated from the cedar grove of Tazekka National Park located south of the city of Taza in Morocco. The culture and purification of the isolated fungus were done on a water agar medium and then on a PDA medium. After the purification of the fungus, a morphological study by electron microscope allowed us to identify the pathogen Pleurostoma richardsiae. A molecular characterization confirmed these results with a coverage percentage of 97% and an identity of 99%. To our knowledge, this is the first report of P. richardsiae in decayed cedar wood.