Articles

WOOD RESEARCH Volume 65, Number 1, 2020
Marcin Jakubowski, Arkadiusz Tomczak, Tomasz Jelonek, and Witold Grzywiński

Variations of wood properties of birch (Betula pendula Roth) from a 23-year old seed orchard

This work presents the results of selected wood properties in birch trees grown on a provenance experiment plot established as a seed orchard. The study concerned: basic density, oven-dry density and compression strength along the grain at a moisture content of 0% and at moisture content above fiber saturation point. Analyses were performed on 971 wood samples collected from 28 trees at the level of breast height. It was found high variability for diameter of breast height (22%) and relatively low for basic density (9%) and oven-dry density (11%). Average basic density was 446.5 kg.m-3 and average oven-dry density was 537.9 kg.m-3. The compression strength at 0% moisture content was four times higher (65 MPa) than the strength at moisture content above the fiber saturation point (16.6 MPa). Most of clones had similar properties within the limits of statistical errors, but a few clones exhibited statistically significant low value.

WOOD RESEARCH Volume 65, Number 1, 2020
Caglar Altay, Ergun Baysal, Hilmi Toker, Turkay Turkoglu, Mustafa Kucuktuvek, Ahmet Gunduz, and Huseyin Peker

Effects of natural weathering on surface characteristics of scots pine impregnated with wolmanit CX-8 and varnished

In this study, it was aimed to investigate the effects of weathering on some surface characteristics such as color and surface roughness changes of Scots pine impregnated with copper-containing chemical such as Wolmanit CX-8 (WCX-8) and varnished with synthetic varnish (SV), cellulosic varnish (CV), and polyurethane varnish (PV) were investigated. Results showed that while the WCX-8 impregnated and PV coated Scots pine specimens showed better color stability than other treatment groups after weathering, only CV coated Scots pine gave the most negative effect on color stability. While, the untreated (control) wood surface turned from red to green and yellow to blue respectively, after weathering, other all treatment groups gave reddish and yellowish tone after weathering. Weathering conditions increased the surface roughness of control (untreated) and other all treatment groups. The control group gave a rougher surface than other treatment groups after weathering. Surface roughness increases were the lower for CV coated Scots pine wood than other treatment groups. The results showed that while WCX-8 impregnation before varnishing gave better color characteristics, generally it caused to increase the surface roughness of Scots pine after weathering.

WOOD RESEARCH Volume 65, Number 1, 2020
Krisztián Andor and Bertalan Bellovics

Analysis of modulus of elasticity of spruce beams under bending with and without fibre reinforcement

The modulus of elasticity has been assumed constant during the finite element (FE) analysis of CFRP reinforced real sized timbers analyzed in load test in laboratory. The latest investigations have shown that it varies significantly during the loading process. Analysis of the modulus of elasticity during the loading provides answers to several questions, by which the FE analysis can be profoundly optimized and yield more accurate estimates. Analysis has been extended to load-modulus functions of previous investigations. Specimens without reinforcement were also included in the investigations, in order to eliminate anomalies of previous measurements and to get easier comparison.

WOOD RESEARCH Volume 65, Number 1, 2020
Tomasz Biadała, Rafał Czarnecki, and Dorota Dukarska

Water resistant plywood of increased elasticity produced from European wood species

The paper investigates the possibility of producing the water-resistant plywood of increased elasticity with use of veneers attained from European wood species, such as alder, birch, beech, pine as well as linden, poplar, willow and spruce. Plywood was produced in two variants. Variant I of plywood was made from various wood species, yet the veneers were of the same thickness. In variant II the centre layer in each case was made from 1 mm thick pine veneer and the face layers were made from 1.4 mm thick veneers of various wood species. The produced plywood was subjected to tests on modulus of rupture, modulus of elasticity and tensile strength, bond quality and compression ratio. Specific values of modulus of rupture and modulus of elasticity were also determined taking into consideration the differences in the thickness of applied veneers. Based on these investigations, the authors concluded that, regardless of the manufacturing method, the highest values of modulus of rupture as well as modulus of elasticity and bond quality are achieved for plywood made from linden, poplar, willow and spruce. The change in the plywood structure (variant II) resulted in a considerable decrease in the values of modulus of rupture and modulus of elasticity (and their specific values) both parallel and across the grain. The lowest values of these parameters were obtained for poplar, linden and willow plywood. What is more, as a result of the applied procedure the bond quality of the produced plywood increased and the compression ratio was reduced. Taking the above into account, we can assume that linden, poplar and willow wood is an optimum choice for the face veneers of plywood with increased elasticity. The centre layer of this kind of plywood can be made from pine veneer of lesser thickness.

WOOD RESEARCH Volume 65, Number 1, 2020
Shupin Luo, Li Gao, and Wenjing Guo

Effect of face layer manipulation on the density profile and properties of low density particleboard

Density reduction has gradually become a trend for the particleboard and furniture industries due to increased price and insufficient supply of wood. However, reduced density of the panels by the simple reduction of the wood material comes along with deterioration of the properties. In this study, to achieve sufficient properties (bending properties in particular), the particle moisture content (MC) and geometry in face layers were manipulated to manufacture low density particleboards (500 kg.m-3), with the core layer composed of a mixture of wood particles (92.5 wt %) and expanded polystyrene (7.5 wt %). This strategy was assumed to increase face layer density and generate a more pronounced vertical density profile, which is expected to improve panel properties. The density profile, mechanical properties and dimensional stability of the particleboards were investigated. Results showed that increasing the moisture content of face layer particles from 8% to 16% or using small-sized particle in face layer resulted in a more pronounced density profile, as well as using fiber in face layer. However, the higher density in the face layer was not necessarily related with better mechanical performance. The optimum physic-mechanical properties were obtained with the board of face layer made of 16% MC fiber, which met the requirements for P2 boards used in dry conditions (EN 312).

WOOD RESEARCH Volume 65, Number 1, 2020
Miroslav Hájek and Pavla Vrabcová

Consideration of forest ecosystem services in environmental management accounting

The environmental management accounting aims at capturing economic and environmental benefits and it should include externalities too. The aim of the paper is to propose a methodological approach for how to include non-market forest ecosystem services in the environmental management accounting so that the information could be used in economic analyzes. For this purpose, it is necessary to identify information relevant to related costs, sales revenues and the value of non-production ecosystem services. It is possible to perform the financial analysis needed for decision making in forest management. In the University Forest Establishment, the rated value of non-market ecosystem services was 3.2 million EUR, and this value was estimated to be twice as much as the value of market ecosystem services. In the Forest Plant Židlochovice, the value of non-market ecosystem services was 0.4 million EUR. Profitability increased from 1.346 to 4.093 and from 1.181 to 3.492.

WOOD RESEARCH Volume 65, Number 1, 2020
Candan Kus Sahin and Busra Onay

Alternative wood species for playgrounds wood from fruit trees

A number of orchard woods have been investigated for suitability in the playgrounds, in the view of responders. In this sense, photos were taken of the specially prepared samples as stimuli, and there were three different groups of respondents. It was observed that the participants were effective in terms of age grouping and material preferences. For group A and C, majority of the participants preferred wooden elements for playground material. However, the majority of participants in group B (50.5%) preferred plastic elements, followed by wooden (31.5%), and then metal (18.0%). Moreover, it was seen that the most significant factors for selection of material for a playground should be safety for both Group A (79%), and C (76.5%), whereas it was aesthetic appearance, for group B (71%). Similar results were found for color properties of wood — the majority of participants of all three groups preferred light colored wooden elements in playgrounds. The results for the aesthetic preferences of wood species judged one-by-one and judged together received similar results. The preference scores for fig wood (Figus canica) is significantly higher than for other wood species, while “wood color” and “aesthetic appearance” are reliable positive predictors to aesthetic preferences.

WOOD RESEARCH Volume 65, Number 1, 2020
Zhonghua Zhagn and Boming Xu

Tang dynasty chair feature design based on Kansei evaluation and eye tracking system

Tang dynasty (AD 618–907) chairs were manufactured during an important period of Chinese furniture development. This paper aims to identify design elements that impact on people’s subjective impressions, so as to guide the design of Tang dynasty style chairs. The study combined eye tracking and Kansei evaluation methods to assess the semantic reception of Tang dynasty chairs. The results showed that the influential factors can be grouped into two main categories: decoration and shape. The decorative features of Tang dynasty chairs that have the most significant impact on visual attention were identified. The study determined that the backrests, armrests, and legs of Tang dynasty chairs design were the most important morphological features. Through these morphological features, we can define the Tang dynasty chair style, guide the design of modern Tang dynasty style chairs, and carry out targeted design of Tang dynasty chair style features.

WOOD RESEARCH Volume 65, Number 1, 2020
Anderson Renato Vobornik Wolenski, Rodrigo Guerra Peixoto, Veronika Fedotova, André Luis Christoforo, and Francisco Antonio Rocco Lahr

Short note: Shear strength estimation model for tropical wood species

For safety reasons, wood strength values are calculated based on their characteristic values. Brazilian national standard (NBR, in Portuguese “Norma Brasileira Regulamentadora”) 7190 (1997) establishes ratios for characteristic strength estimation and three forms of wood characterization, with an emphasis on the simplified procedure for common species, which allows obtaining the strength characteristic values through equations correlating different mechanical properties. The present work evaluates the accuracy of the relation proposed by NBR 7190 (1997) of shear strength along the grain (fv0,k) to compression strength along the grain (fc0,k) (fv0,k=0.12 fc0,k). 960 experimental measurements of shear and compression strength values were performed for 40 hardwood species, and the precision of the relation proposed by the Brazilian standard was evaluated using the analysis of variance (ANOVA) method. Linear, exponential, logarithmic, and geometric regression models were used as an alternative to the NBR relation for shear strength estimation. The statistical analysis revealed that the geometric regression is the model of best fit.

WOOD RESEARCH Volume 66, Number 3, 2021
Hasan Hüseyin Taş, Bilge Arslan, and Hülya Kalaycıoğlu

Effects of polymer additives on some mechanical and physical properties of cement bonded particleboards

The effects of some polymer additives, also called super plasticizers, on selected physical and mechanical properties of cement bonded particle board were investigated. Two different kinds of poly carboxylic ether (PF300, DX40) and a melamine based polymer (300M) were added to the wood cement mixture. The ratios of polymer additives to the wood cement mixture were 1%, 1.2% and 1.4%. Cement bonded particleboards were manufactured with wood/cement (w/w) ratio of 1:3; target density of 1300 kg.m-3, and CaCl2 content of 5%. The cement bonded particleboards were tested for water absorption (2 and 24 hour), thickness swelling (2 and 24 hour), bending stiffness and strength and internal bond strength. Results of the study showed that most of the polymer addition decreased water absorption and thickness swelling of the boards. Replacement of cement with polymers increased internal bond strength and bending stiffness of the boards while bending strength was slightly reduced. Use of small amount of super plasticizers significantly improves most of the board properties.

WOOD RESEARCH Volume 66, Number 3, 2021
Haiyan Fu, Xinyue Zhao, Patrick Adjei, Zheng Wang, and Xiaoli Wu

Study and analysis on sound absorbing and noise reducing performance of timber construction wall based on acoustic spiral matasurface

Based on acoustic spiral metasurface, a spiral structural layer was designed to apply to timber construction interior wall. The sound absorption coefficient was measured by impedance tube method and compared with Helmholtz resonance structural layer, solid structural layer and air layer in traditional wall. The results show that the combination of the spiral structural layer and the wall can optimize the sound absorption performance of the wall in the medium and low frequency. Without reducing the overall sound-absorbing performance of the wall, can achieve perfect sound absorption in some medium and low frequency sound bands.

WOOD RESEARCH Volume 66, Number 3, 2021
Chunyan Lv, Caijuan Zhang, XINJIE ZHOU, Mingyu He, LILI YU, and ZHENZHONG TANG

Effect of different pre-treatments on the permeability of glue-laminated bamboo

In this study, hydrothermal treatments (duration: 2 h, 5 h, 8 h; temperature: 60°C, 80°C, 100°C), ultrasonic treatments (duration: 60 min, 90 min, 120 min; temperature: 40°C, 50°C, 60°C; ultrasonic power: 400 W, 600 W, 800 W) and freeze-drying treatments (vacuum degree: 0.05 mbar, 0.1 mbar, 0.5 mbar, 1.0 mbar, 1.7 mbar) were performed respectively to improve the permeability of glue-laminated bamboo. The effects of different pre-treatments on the permeability were compared according to the water absorption test and the mercury intrusion porosimetry test. The microstructure change of the samples was observed by scanning electron microscope (SEM). The results showed that freeze-drying treatment was an effective way to increase the permeability of the samples, in which the water absorption rate can be increased by 47%, and the porosity can be increased by 10% at 0.5 mbar vacuum. From SEM analysis, some small holes appeared in the cell wall of the freeze-dried samples, because he free water inside the samples was changed into ice, and the volume became larger, and the pore diameter of the bamboo was enlarged.

WOOD RESEARCH Volume 66, Number 3, 2021
Intan Fajar Suri, Byantara Darsan Purusatama, Seung Hwan Lee, Nam Hun Kim, Wahyu Hidayat, Shalehudin Denny Ma’ruf, and Fauzi Febrianto

Characteristic features of the oil-heat treated woods from tropical fast growing wood species

This study aimed to evaluate the effect of oil-heat treatment on the anatomical, physical, and chemical properties of the tropical fast-growing wood species as gmelina (Gmelinaarborea) and mindi (Melia azedarach) wood. Vessel lumen area and diameter in radial and tangential direction of both species increased with increasing temperature. The fiber lumen areas in both woods were remarkably decreased by oil-heat treatment, and the fiber wall area increased considerably with increasing temperature. Both woods tended to gain weight after heat treatment at 180°C and 200°C, and then lose weight after heat treatment at 220°C. The density of mindi increased greatly at 180°C and 200°C and slightly decreased at 220°C. The dimension of the specimens in tangential direction increased with heat treatment, but the rate decreased with increasing temperature. The relative crystallinity and crystallite width of the heat-treated woods were greater than those of the untreated wood. In the Fourier transform infrared analyses, the peaks from the carbohydrates were changed after oil-heat treatment, mainly due to the degradation of hemicellulose. Consequently, it was revealed that the heat treatment affected various properties of gmelina and mindi woods. Differing characteristics between the species were also noted.

WOOD RESEARCH Volume 66, Number 3, 2021
Ahmet C. Yalinkilic, Eyup Aksoy, Musa Atar, Hamza Cinar, and Hakan Keskin

Eco-design: Impacts of bleaching chemicals and varnishes on the amount of carbon dioxide in the combustion of oriental beech (Fagus orientalis Lipsky)

This study was carried out to determine the effects of bleaching chemicals and varnishes on the amount of carbon dioxide (CO2) in the combustion of oriental beech (Fagus orientalis Lipsky). For this purpose, samples of Oriental beech prepared according to ASTM D 358 contain 18% R1 = (NaOH + H2O2), R2 = (NaOH + Ca(OH)2 + H2O2), R3 = (Na2S2O5 + H2C2O4), R4 = (NaSiO3 + H2O2), R5 = (KMnO4 + Na2S2O5 + H2O2) solution groups, after bleaching with solution groups, water based, synthetic, polyurethane and acrylic varnish were applied according to ASTM D 3023 and combustion tests were carried out in accordance with ASTM E 160-50. Gas measurements were made with the SIGMA 74172 NSU flue gas device during the combustion process. As a result, in respect to the burning types; the highest amount of CO2 (ppm) was found in the self-combustion (8.468 ppm) while the lowest was obtained from the flame combustion source (4.599 ppm). In respect to the types of bleaching; the highest in R5 (7.458 ppm) and the lowest in R3 (4.059 ppm) were found. According to the varnish types; the highest value was found in the synthetic varnish (8.261), and the lowest value was found in the acrylic varnish (4.772 ppm). According to combustion type + bleaching solution + varnish type interaction, the highest values were found for without flame combustion (II) + R3 + Sn (18.40 ppm) and lowest for flame source combustion (I) + R5 + Pu (0.600 ppm). Consequently, the highest values for combustion gases were found in samples of oriental beech wood samples treated with water-based varnish with R1 solution. According to this, in terms of human health and life safety, possibility of fire in places, R3 solution and acrylic varnish may be used in the related industries.

WOOD RESEARCH Volume 66, Number 3, 2021
Huijun Dong, Mohsen Bahmani, Miha Humar, and Sohrab Rahimi

Fiber morphology and physical properties of branch and stem wood of hawthorn (crataegus azarolus l.) grown in zagros forests

This study aims at investigating the effect of three altitude levels (below 1800 m, 1800-2000 m and above 2000 m) on the physical and biometric properties of stem-wood and branch-wood of hawthorn species. Moreover, the relationship between wood dry density and volumetric swelling, fiber length, fiber diameter, cell wall thickness were studied. Results indicated that altitude had significant effects on the dry density, volumetric swelling and fiber length of stem wood while did not significant effects on the density of branch wood. Additionally, some physical and biometric properties had relatively greater correlation coefficients in branch wood than in stem wood whereas others had higher coefficients in stem wood compared to branch wood. Deep understanding of properties this wood species will provide a fresh insight into the relationship between wood properties and environmental factors.

WOOD RESEARCH Volume 66, Number 3, 2021
Wang Wei, Hui Shen, Haiqiao Zhang, Yang Zhang, Yanji Zhou, and Danyang Zhao

Characterization of aromatic fiberboard

For use as decoration panels, wood fiber was used to prepare a new type of aromatic fiberboard using hot-press technology that mixes spices and adhesives. Experiments showed that the use of different proportions of two kinds of spices, wormwood and lavender, mixed with waterborne acrylic adhesives, had a slight influence on the curing time and viscosity of the glue. The different mixtures equally affected the physical and mechanical properties of the fiberboard and the smells similarly affected brain wave frequencies. The experimental results showed that a 20% proportion of lavender and wormwood was optimal compared with 5%, 10%, and 15%, and this amount also provided the best health-care effect. This work provides the experimental data and a theoretical basis to achieve pharmacological and health-care effects for the development of aromatic and other special kinds of fiberboard for industrial applications.

WOOD RESEARCH Volume 66, Number 3, 2021
Seong Hyun Kim, Do Hoon Kim, Jae Ik Jo, Jong Ho Kim, Seung Hwan Lee, Jung Kee Choi, and Nam Hun Kim

A comparative study on the physical and mechanical properties of Dahurian larch and Japanese larch grown in Korea

To compare the wood quality of Dahurian larch and Japanese larch growing in Korea, the physical and mechanical properties were examined using the Korean standards. The proportion of heartwood was 82% and 72% in Dahurian and Japanese larch, respectively. The percentage of latewood was 42% in Dahurian larch and 35% in Japanese larch. The growth ring width of Dahurian larch was narrower than that of Japanese larch. Dahurian larch showed about 20% higher green moisture content compare to Japanese larch wood. Density and shrinkage of Dahurian larch were higher than Japanese larch. Axial compression strength, young`s modulus in compression, and shearing strength in heartwood of Dahurian larch were 11 MPa, 686 MPa, and 2.3 MPa, respectively, showing higher value than Japanese larch. The hardness was in the range of 13.8–38.7 MPa in Dahurian larch and 17.7–48.4 MPa in Japanese larch. The compression strength parallel to the grain and shearing strength in both species were significantly correlated with oven-dried density. Besides, the hardness in Dahurian larch was significantly correlated with latewood percentage and oven-dried density. In conclusion, the differences in the properties of both species were revealed and the results can be used for quality indices of both wood species.

WOOD RESEARCH Volume 66, Number 3, 2021
Jiangyi Chu, Jinghui Jiang, Chusheng Qi, and Yongdong Zhou

Study on concentrations of acids and alcohols emitted by pinus radiata during high-temperature drying

The purpose of this paper is to investigate the influence of kiln temperature, relative humidity and wood moisture content on the content of acid and alcohol released in the drying process of high temperature kiln by studying the radiated pine sawn timber of 40mm thickness. The drying temperature was between 101°C and 115°C, the relative humidity in the drying kiln was reduced from 86.1% to 39.6%, the moisture content of the lumber was reduced from 106.16% to 11.98%, and gas extraction was executed nine times with an extraction speed of 1.0 L•min-1 and a sampling time of 30 min. The concentrations of acids and alcohols were analyzed by HPLC. The results showed that the concentrations of formic acid, acetic acid, and methanol emitted in the kiln during drying were 215.6-748.2, 4148.8-16803.2, and 6381.9-15648.9 mg•m-3, respectively, and these concentrations were significantly higher than the relevant standards. The concentrations of the emitted formic acid and acetic acid were proportional to the drying temperature, the concentrations of the emitted formic acid and acetic acid were inversely proportional to the relative humidity in the kiln and the moisture content of the lumber. The concentration of the emitted methanol was independent of the drying temperature, relative humidity in the kiln, and moisture content of the lumber. It is therefore suggested that formic acid, acetic acid, and methanol be separately recovered during the high-temperature drying of Pinus radiata lumber.

WOOD RESEARCH Volume 66, Number 3, 2021
Petar Antov, Viktor Savov, Nikolay Neykov, and Ľuboš Krišťák

Effects of hot pressing parameters on the properties of hardboards produced from mixed hardwood tree species

In this work, wet-process fibreboards (hardboards) were produced in the laboratory using industrial wood fibres of the species European beech (Fagus sylvatica L.) and Turkey oak (Quercus cerris L.) at the total volume of 40%, and white poplar (Populus alba L.) at 60% volume. The effects of hot pressing pressure (varied from 3.3 MPa to 5.3 MPa) and pressing time (from 255 s to 355 s) on the physical and mechanical properties of hardboards were investigated and optimal values of the parameters for fulfilling the European standard requirements were determined. It was concluded that hardboards with acceptable physical and mechanical properties may be produced from 60% poplar wood waste and residues, combined with 40% hardwood raw materials (beech and oak) by regulating the hot pressing regime only, i.e. pressure and pressing time. The following minimum parameters for producing hardboards from mixed hardwood tree species were determined: a pressure of 4.6 MPa and a pressing time of 280 s.

WOOD RESEARCH Volume 66, Number 3, 2021
Tomasz Jelonek, Witold Pazdrowski, Joanna Kopaczyk, Magdalena Arasimowicz-Jelonek, and Arkadiusz Tomczak

Biosocial diversity of scots pine (pinus sylvestris l.) in a tree stand in relation to chosen hydraulic conductivity indicators of the stem

The research focused in determining the lignification indicator of fresh needled springs and the mass of fresh needles in reference to the lignin content in tracheid walls of peripheral area of the stem (MFT/LC and MFN/LC) of Scots pine differentiated as far as its biosocial position within the community expressed by Kraft’s classification. The material for the analysis came from mature pine stands growing on North European Plain, on the territory of Poland. Chemical and structural analyses of wood encompassed the area of mature sapwood, i.e. thickness of the last 10 annual rings located at 1.3 m (DBH). It seems that the noticed differences values of both indicators (MFT/LC and MFN/LC) in pines belonging to the first three Kraft’s biological classes are connected with physiological, physical and structural conditionings of water transport with minerals in xylem and are closely connected with competition for sunlight, water, nutrients and living space.