Scielo RSS <![CDATA[Maderas. Ciencia y tecnología]]> vol. 24 num. lang. es <![CDATA[SciELO Logo]]> <![CDATA[Optimization of CNC operating parameters to minimize surface roughness of <em>Pinus sylvestris</em> using integrated artificial neural network and genetic algorithm]]> Abstract: The surface roughness of wood is affected by the processing conditions and the material structure. So, optimization of operation parameters is very crucial to have minimum surface roughness. In this study, modeling and optimization of surface roughness (Ra) of Scotch pine (Pinus sylvestris) was investigated. Firstly, the samples were cut under different conditions 8 mm, 9 mm and 11mm depth of cut and 12 mm, 14 mm and 16 mm axial depth of cut) in computer numerical control (CNC) machine, and then surface roughness (Ra) values of samples were calculated. Then a prediction model of surface roughness was developed using artificial neural networks (ANN). Optimization process was carried out to reach minimum surface roughness of wood samples by the genetic algorithm (GA) method. MAPE value of the ANN model was found lower than 4,0 %. The optimum CNC operation parameters were 1874,5 rad/s, 3,0 m/min feed rate, 9,7 mm depth of cut and 12 mm for axial depth of cut for minimum surface roughness. As a result of study, surface roughness of Scotch pine wood can be modeled and optimized using integrated ANN and GA methods by saving time and cost. <![CDATA[Mass transfer properties of <em>Acacia mangium</em> plantation wood]]> Abstract: This study investigated the mass transfer properties (permeability and mass diffusivity) in the longitudinal, radial and tangential directions of plantation-grown Acacia mangium in VinhPhuc province,northeast, Vietnam. These properties will be used to complement a conventional drying model in the future. Measurements of gas and liquid permeability were performed using a Porometer (POROLUXTM1000). Mass diffusivity was determined in a constant humidity and temperature chamber using PVC-CHA vaporimeters. Results showed the gas permeability was significant higher than liquid with the descending order of longitudinal, radial, and tangential directions. The permeability anisotropy ratios from the longitudinal to transverse directions of Acacia mangium were much lower than other published species. However, the obvious anisotropy ratios from radial to tangential for both permeability and diffusivity, is one of concerns as they can exacerbate defects during drying. Besides, the high permeability and diffusivity of Acaciamangium compared to some other species reported compounds its relatively fast drying rate. <![CDATA[Plywoods of northeast Argentinian woods and soybean protein-based adhesives: Relationship between morphological aspects of veneers and shear strength values]]> Abstract: Three-ply plywoods were produced using pine and Eucalyptus northeast Argentinian woods. A no-added formaldehyde biobased-adhesive was used for assembly, based on chemically modified soy protein concentrate. In this work we focused on the relationship between bonding quality parameters of the plywoods and the morphology of the glued line. Wood characteristics such as contact angle, roughness, density and moisture content were measured prior to plywood assembly. Bonding quality parameters (percentage of wood failure and shear strength) of the plywood were measured according to Argentinean standard and the results were evaluated with respect to microscopic observations of the glue joint. Eucalyptus wood was suitable for plywood interior condition applications, while pine barely exceeded the standards imposed by the norm. <![CDATA[A novel method for producing a glulam from the wood of peeler cores]]> Abstract: This study presents an opportunity for rational utilization of poplar wood peeler cores in the production of glued laminated timber (glulam) beams. An approach for optimal use of small-diameter raw material with a circular cross-section is also proposed in order to obtain a final product in a significantly high quantitative yield. The applied novel method of sawing the peeler cores and subsequent combination of gluing the obtained lamellas allows to achieve: reduction of labor and energy consumption in the processing; rational utilization of this waste raw material; obtaining a product sought by consumers; opportunity to implement technology for the production of glulam from peeler cores. The results showed that sawing the peeler cores and obtaining lamellas with a trapezoidal cross-section leads to a high quantitative yield of 76,3 %. The final quantitative yield in subsequent technological operations in the manufacturing of engineered wood of glulam type reaches 48,8 % of the volume of raw material. In addition, equations have been working are used for the determination of the most suitable sizes of the lamellas, depending on the diameter and the kerf width. <![CDATA[Simultaneous treatment with oil heat and densification on physical properties of <em>Populus</em> × <em>Canadensis</em> wood]]> Abstract: Samples of wood from Populus × canadensis (9,5 % moisture) were treated with olive oil at 195 °C simultaneously with 15 % or 30 % compression densification, and the results were compared with samples subjected to oil heat treatment without densification, and control samples. The density of the treated samples increased by 18 %, 43 % and 1,5 % respectively, and barely changed over the six subsequent months stored inside the laboratory room (at approximately 65 % RH, 20 °C). This was due to the fact that the slight weight increment caused by the additional moisture content was offset by the increase in volume from the springback effect. When subjected to atmospheres with different relative humidities, the treated samples stabilised at the same time as the control samples, although the treated samples had a significantly lower moisture absorption than the control samples. It was also observed that the hygroscopic shrinkage in oil heat densification treatment samples was approximately half those of the control samples. The initial densification was partially lost as a result of springback: approximately 3 % in the first springback at a relative humidity of 65 % RH, and an additional 4 % in the second springback to a relative humidity of 85 % RH. Once this latter relative humidity had been attained, no new losses in densification were observed. The ageing of the oil used in the treatment caused a slight loss of densification in the densest samples. <![CDATA[Fumigation of imported <em>Tectona grandis</em> and southern yellow pine with <em>Pongamia pinnata</em> seed oil against sapstain and mould]]> Abstract: An eco-friendly alternative of Pongamia pinnata seed oil was tested for fumigation of imported Tectona grandis and Pinus spp. (Southern yellow pine) against sap stain and mould fungi at 25°C± 2°C and 75 % ± 5 % relative humidity. Veneeer and block samples of both species, and Petri dishes with agar media were fumigated with three different concentrations (w/v) of Pongamia pinnata seed oil and exhibited significant inhibition of fungal growth in comparison to the control sets, with the highest concentration of 6,4 g/ 8 mL3 proving to be the most lethal. Tectona grandis exhibited no infestation of sapstain and mould in either type of specimens whereas highly perishable Southern yellow pine displayed slight infestation of 4 % and 5 % with 1,6 g/ 2 mL3 of Pongamia pinnata seed oil for venner and block specimens as compared to 18 % and 20 % infestation observed in respective controls. The infestation on Southern yellow pine reduced to 1 % and 2 % respectively for veneers and blocks with 4 g/ 5 mL3 of Pongamia pinnata seed oil and was completely inhibited at 6,4 g/ 8 mL3 for both type of Southern yellow pine specimens. Petri plates returned similar findings where all higher concentrations inhibited mould growth completely and the lowest concentration exhibited meagre mould growth. Sapstain was inhibited successfully by all three concentrations of Pongamia pinnata seed oil on agar media. <![CDATA[Some surface characteristics of oriental beech wood impregnated with some fire-retardants and coated wıth polyurea/polyurethane hybrid and epoxy resins]]> Abstract: This study was made to determine surface characteristics such as colour, gloss, and surface hardness changes of Oriental beech (Fagus orientalis). The wood specimens were firstly impregnated with some fire-retardants (FRs) and primed with epoxy resin (EPR) and then coated with polyurethane/polyurea hybrid resin (PUU). Oriental beech was impregnated with 3 % aqueous solution of boric acid (BA), borax (BX), boric acid and borax mixture (1:1), and ammonium sulphate (AS). While Sikafloor®-156 was used for epoxy coating (EPR), Sikalastic®-851 R was used for polyurethane/polyurea hybrid coating (PUU). According to our results, all treatment groups gave negative lightness stability values after accelerated weathering. The colour stability of epoxy resin coated Oriental beech was higher than that of polyurethane/polyurea hybrid resin coated Oriental beech. Except for boric acid impregnated and polyurethane/polyurea hybrid resin coated Oriental beech, all fire-retardants treatment before polyurethane/polyurea hybrid resin and epoxy resin coatings decreased the gloss losses of Oriental beech after accelerated weathering. Fire-retardants impregnation before epoxy resin and polyurethane/polyurea hybrid resin coatings improved the surface hardness values of Oriental beech after accelerated weathering. <![CDATA[Physical properties of palmyra palm wood for sustainable utilization as a structural material]]> Abstract: Physical properties are major characteristics that validate biomaterials' adaptability to commercial utilization. The moisture content, density, swelling, and shrinkage within male and female Borassus aethiopum were assessed. Green and dry moisture content, and density were tested with the oven-dry method while swelling and shrinkage were evaluated using the water-saturation test and oven-dry methods respectively. Unlike moisture content, density decreased towards the crowns and radially from the peripheries to their cores. Directional swelling decreased as: Radial &gt; Tangential &gt; Longitudinal. Volumetric swelling was greatest at the core of the base (6,99 %) but at least at the periphery within the middle of the male (2,89 %). However, the female recorded much swelling at the core of its mid-portion (6,23 %) and least (4,01 %) at the crown periphery. Directional shrinkage decreased identically as the male variety while the volumetric shrinkage for both varieties was not consistent. The peripheries had less moisture content, better dimensional stability and density (which influences wood strength) at the butt than those of the core indicating the peripheries would maintain its original dimension and strength when subjected to environmental changes and be more viable for structural works than the core. <![CDATA[Physical, chemical and mechanical characterization of <em>Acrocarpus fraxinifolius</em> cultivated in Sao Paulo]]> Abstract: Indian cedar (Acrocarpus fraxinifolius) is a wood species that occurs naturally in India, Myanmar (Burma) and Bangladesh, and has a high commercial value, with characteristics like mahogany and native cedars. The planting of Indian cedar has been undertaken in Brazil, but there is little information available regarding the characterization of the species. Therefore, considering its timber potential and its possibility of development in the country, the present work aimed to evaluate the physical, chemical, and mechanical properties of 9-year-old Indian cedar wood, planted in the southern region of Brazil. A low specific mass (502 kg/m³), low average dimensional stability (anisotropy coefficient of 2,09 %) was observed, in addition to the low content of extractives (1,94 %). From the mechanical characterization, an average value for the elastic modulus of 8963 MPa was obtained, and for the compressive strength parallel to the grain the average and characteristic values were 32,14 MPa and 21,46 MPa, respectively. This indicates that this wood belongs to resistance class C20 (dicotyledons). The results obtained classify the wood for use in light, external, or internal civil construction. <![CDATA[Evaluación de impactos ambientales de viviendas en madera: El caso de “La casa Uruguaya”]]> Resumen: Varias medidas se están llevando a cabo en Uruguay para reducir las emisiones de CO2 a la atmósfera, entre las que destaca la modificación de la matriz energética. En estos últimos años más del 90% de la energía eléctrica que se produjo provino de fuentes renovables, tales como la eólica, la hidroenergía o la biomasa. A pesar de estos progresos, el sector de la edificación, la construcción y el transporte continúan siendo en gran parte responsables de los impactos ambientales que producen las actividades humanas en el país. Por otra parte, diversos estudios muestran el avance en el desarrollo de metodologías de cálculo y la definición de estrategias que permitan reducirlas. En ese sentido la metodología del Análisis del Ciclo de Vida (ACV) es considerada una de las más trasparentes y reconocidas por la comunidad científica internacional. Este estudio tiene por objetivo el desarrollo de una propuesta metodológica basada en el ACV, para calcular los impactos ambientales que producen los edificios residenciales en madera durante su ciclo de vida. La verificación experimental se desarrolla a través del caso de “La Casa Uruguaya”, una vivienda social unifamiliar construida en madera. La metodología propuesta permite, a partir de la fase avanzada del diseño de la vivienda, obtener resultados de los impactos ambientales que se producen durante su ciclo de vida completo. Los resultados demuestran la relevancia de las etapas de uso (uso de energía, mantenimiento, reparación, rehabilitación y sustitución) y de producto (extracción de materias primas, fabricación y transporte) sobre el resto de las fases del ciclo de vida consideradas.<hr/>Abstract: Several actions have been taken in Uruguay to reduce CO2 atmospheric emissions, including modification of the energy matrix. In recent years more than 90% of electricity was produced by renewable sources, such as wind power, hydro (run-of-river) or biomass. Despite this fact, the building, construction, and transport sectors are still great responsible of the environmental impacts produced by human activities. Moreover, several studies show advances of methodologies that allow the environmental impact calculation and the definition strategies for reduction. Life Cycle Assessment (LCA) is considered one of the most transparent and recognized method by the international scientific community. This study aims to develop a methodology based on LCA, to calculate the environmental impacts produced by timber buildings during their life cycle. The case study verification focuses on “La Casa Uruguaya”, a social single-family timber house. The proposed methodology allows obtaining the environmental impacts of the whole life cycle, from the detailed design stages of design. Results show the relevance of the use stage (energy consumption, maintenance, repair, refurbishment and replacement) and product stage (raw material, manufacture and transport) compared to the rest of the life cycle stages included in the study. <![CDATA[An evaluation of clove (<em>Eugenia caryophyllata</em>) essential oil as a potential alternative antifungal wood protection system for cultural heritage conservation]]> Abstract: This paper investigates the potential of clove (Eugenia caryophyllata) essential oil (C-EO) as a wood protection system for use in cultural heritage conservation. The preventive and curative antifungal efficacy of C-EO was compared to a boron containing wood preservative (Diffusit S) in two laboratory tests on European beech (Fagus sylvatica) and Scots pine sapwood (Pinus sylvestris) mini-blocks. Non-sterile, air-infected wood samples were employed in the first test, while wood samples with active attack, as result of inoculation with three fungal strains isolated from cultural heritage sites, in the second test. Untreated controls and C-EO-treated wood blocks were incubated up to 150 days to monitor and quantify fungal growth. The experimental results showed antifungal efficacy of C-EO to be higher than that of the boron wood preservative at the concentrations used. Concentrations of C-EO 5 % - 10 % in ethyl alcohol prevented mould growth for at least 150 days, while a concentration of 10 % delayed or suppressed active attack by decay fungi. This effect, determined up to 90 days of incubation, was dependant on the type of fungus. <![CDATA[Preparation of plywood panels using waste milk pouches as an adhesive]]> Abstract: Recycling of single use plastic like milk pouches, oil pouches, etc. for high value products can have significant environmental, social and economic implications. The present study focuses on the utilization of waste milk pouches made out of low-density polyethylene as the bonding agent in preparation of plywood panels. Plywood panels with varying content of polymeric content (milk pouch layers) were prepared and evaluated for physical and mechanical properties. The results indicated that with increase in the dosage of milk-pouch content, both physical as well as mechanical properties of the plywood improved substantially. There was nearly three folds difference in modulus of rupture of panel prepared with 80 g/m2 and 310 g/m2 polymer content. Similarly, tensile strength, modulus of elasticity also increased significantly with increase in polymer content. The glue shear strength, which is very important for plywood, was found to be influenced by the quantity of polymer. Glue shear strength for panel with 80 g/m2 polymer was 0,75 MPa which increased to 1,90 MPa in panel with 310 g/m2 polymer content. It was observed that for strong bonding it is essential that the quantity of polymer should be sufficient enough to penetrate into the pores of wood creating a mechanical interlocking of veneers. The study opens up the scope of recycling of waste milk pouches in the preparation of formaldehyde free plywood. <![CDATA[Particle image velocimetry technique and ultrasound method to obtain the modulus of elasticity of <em>Bertholletia excelsa</em> wood]]> Abstract: Non-destructive techniques for characterizing materials in-service have been increasing in importance. Thus, it is relevant to assess the potential of non-destructive techniques for solid materials. This work aimed to determine the modulus of elasticity of Bertholletia excelsa wood using the particle image velocimetry technique and the ultrasound method to compare the results with the conventional methodology. For this purpose, samples of Bertholletia excelsa were made using a circular saw. The samples were evaluated for sound propagation to calculate the modulus of elasticity using ultrasound equipment. Subsequently, they were subjected to the compression parallel to grain test in a universal testing machine. The samples were marked and monitored during the loading session, with the repeated capture of images using a professional camera. The deformation values obtained were used to estimate the modulus of elasticity using the particle image velocimetry technique. The mean values of modulus of elasticity found were 17403 MPa for ultrasound, 15589 MPa for the particle image velocimetry technique, and 15333 MPa for the universal testing machine. The particle image velocimetry technique was considered to be statistically similar (Tukey α = 0,05) to the other methods tested. The linear coefficient of determination (R2) between the particle image velocimetry technique and the universal testing machine was 0,95, a high and satisfactory value. Thus, the particle image velocimetry technique and the ultrasound method are valid to estimate the modulus of elasticity of Bertholletia excelsa wood and possibly of woods with similar technological characteristics. <![CDATA[Mechanical, thermal, and morphological behaviour studies on coconut shell and palm kernel filler biocomposite]]> Abstract: In the present work, the composite materials were prepared from coconut shell powder, palm kernel powder, and epoxy resin. The addition of coconut shell powder was considered when preparing the composite samples, and mechanical properties such as tensile strength, hardness, impact, bending strength, physical behavior water absorption, as well as morphological tests, were conducted using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscope, and Thermogravimetric Analysis for both the prepared composite material boards and chipboard. The minimal variation of tensile stress and percentage of elongation between the 50 % coconut shell powder composite material and the wooden chipboard material is 4,44 MPa and 1,00 %, respectively, according to the findings of experimental tests.The lowest compressive stress and hardness variations between coconut shell powder composite material and wooden chipboard are found to be 0,14 MPa and 3,2 MPa, respectively. It is determined that the composite materials made from waste shell powders and epoxy resin are suitable for applications such as panel boards, automotive interior dashboards, roof sheets, and doors. <![CDATA[Effectiveness of European oak wood staining with iron (II) sulphate during natural weathering]]> Abstract: Artificial graying of wood can be solution for contemporary trends of using uncoated wood for the arrangement of external architecture. The presented work was aimed at investigation of colour changes of European oak (Quercus sp.) wood surface treated with iron (II) sulphate. Three different procedures differing in time (2 h and 24 h) and temperature (20 °C and 70 °C) were used, as well as three different concentrations of aqueous iron (II) sulphate solutions (10 %, 20 %, 30 %). Beside the colour itself, it was evaluated the stained oak wood discolouration due to natural weathering. Thanks to iron (II) sulphate, wood colour changed to dark grey. In general, the colour changes on tangential section of wood were higher than those on radial section what was result of wood structure, in particular parenchyma cells arrangement in wooden rays. Contrary to expectations, the concentration of the iron (II) sulphate solution was not of significant importance for wood staining. Usage of concentrations higher than 10 % for the modification of the colour of wood gives the same effects. However, with increasing solution used to wood staining, the colour stability of the wood decreases during external exposure. The parameters of the procedure were not significantly affected. This allows the application of the simplest and least time-consuming modification method to be considered. <![CDATA[Applying colorimetry for wood differentiation of fabaceae species grown in southern Brazil]]> Abstract: Because of the need for identification of forest species, especially for detection of illegal wood trade, the objective of this study was to evaluate the potential of colorimetry for differentiation of Inga vera Willd., Muellera campestris (Mart. ex Benth.) M.J. Silva &amp; A.M.G. Azevedo and Machaerium paraguariense Hassl., species of the Fabaceae family, native to the Araucaria Forest in the state of Santa Catarina, southern Brazil. Discs at breast height were collected from three trees of each species and the colorimetric parameters (L*, a*, b*, C* and h) and visible spectra were evaluated in different radial position of the trunk (near bark, intermediate and near pith) and three different anatomical sections (transversal, radial and tangential surfaces). Mean values of hue angle (h) among the colorimetric parameters resulted in the highest potential for species discrimination. With respect to radial trunk position and anatomical section, parameters a* (green-red) and h were not statistically different, independent of the wood samples evaluated. For other parameters (L*, b* and C*), each species presented distinct results. Principal component analysis with second derivative of visible spectra discriminated all species. Colorimetry associated with chemometrics allowed to distinguish I. vera, M. campestris and M. paraguariense. <![CDATA[Comparative study on weathering durability property of phenol formaldehyde resin modified sweetgum and southern pine specimens]]> Abstract: The effects of low molecular weight phenol formaldehyde resin on weathering durability property of sweetgum (Liquidambar styraciflua) and southern pine (Pinus taeda) specimens were studied using six wet-dry cycles with ultraviolet light accelerated weathering test following ASTM via evaluating the water repellent efficiency, dimensional stability, and crack formation of wood. The results showed that 1) the water repellent efficiency of treated quarter-sawn sweetgum specimens was higher than those of treated quarter-sawn and flat-sawn southern pine specimens; 2) the dimensional stabilities of sweetgum and southern pine specimens were all improved by impregnating low molecular weight phenol formaldehyde resin, especially for sweetgum; 3) there were clearly more cracks on exposed ends and surfaces of all treated sweetgum and southern pine specimens than those on control ones, indicating that the low molecular weight phenol formaldehyde resin modification used in this study were not able to improve the anti-cracking properties of sweetgum and southern pine specimens. Generally, the sweetgum was more suitable to be impregnated with low molecular weight phenol formaldehyde resin than southern pine with the procedure described according to dimensional stability and water repellent efficiency, in order to improve the weathering durability. <![CDATA[Effect of the thermal treatment on the chemical components, sorption, and shrinkage properties of <em>Tectona grandis</em> juvenile wood]]> Abstract: The effect of thermal treatment on the chemical components, equilibrium moisture content (EMC), and shrinkage of teak juvenile wood was studied. Heartwood and sapwood samples were thermally-treated at 180 ºC and 200 ºC. Extractive, Klason lignin, holocellulose, and α-cellulose contents, as well as pH on untreated and thermally-treated woods, were determined. The EMC was reached at five relative humidity (RH) levels using saturated salt solutions: 86 % (KCl), 76 % (NaCl), 58 % (NaBr), 33 % (MgCl2), and 0 % (P2O5). Linear and volumetric shrinkages were calculated for all EMCs. The ratio of sorption (S), coefficient of shrinkage (h), and fiber saturation point (FSP) were also determined. Thermally-treated wood exhibited lower holocellulose and α-cellulose contents than untreated wood and increased acidity due to degradation of the hemicelluloses. The thermal treatment reduced the EMC of heartwood and sapwood. However, sapwood was more sensitive to RH variations than heartwood regardless of the treatment. Thermally-treated woods had higher hygroscopic and dimensional stabilities, and lower FSP than untreated wood. The thermal treatment did not affect radial shrinkage of the heartwood between 33 % and 86 % RH. Heartwood was more sensitive to the effect of the thermal treatment on shrinkage and degradation of cell wall polymers compared to sapwood. <![CDATA[Influence of growth parameters on wood density of <em>Acacia auriculiformis</em>]]> Abstract: Understanding the drivers of wood density variation both within a tree and between trees is important in predicting the quality of wood logs and improving this quality through adequate forestry management. This study examined the effect of the diameter growth of Acacia auriculiformis on its wood density variation. The study was conducted in the South of Benin in four plantations of Acacia auriculiformis. Near infrared spectroscopy (NIRS) method was used to predict the basic density of 225 tree wood cores of Acacia auriculiformis. A predicting model of the average tree density using the diameter as predictor was established. The relationship between wood density and tree diameter was best described by a linear mixed-effect model. The average wood density of trees increased with the diameter. The study concluded that the quality of the species logs can be improved through regular thinning and genetic selection. <![CDATA[Evaluation and comparison of control and heat treated L-shape furniture joints produced from Scotch pine and ash wood under static bending and cyclic fatigue bending loadings]]> Abstract: This study investigated how the mechanical properties of L-shape joints produced from heat treated Scotch pine or ash wood behaved under cyclic fatigue loading and compared this with the mechanical properties of non-heat treated wood materials. Additionally, static bending performances of the L-shape of joints were investigated and compared to fatigue bending performance of same type of joints. Results indicated that increasing number of staple from 6 to 8 and density generally increased static bending of L-shape joints. Static bending resistance of L-shape joints produced from control Ash wood significantly higher than those of L-shape joints produced from heat treated Ash wood while no significant difference were observed between static bending resistance L-shape joints produced from control Scotch pine and L-shape joints produced from heat treated Scotch pine wood. The fatigue bending resistances of L-shape joints produced from heat treated samples generally passed and failed the same loading steps with those produced from control samples which means both L-shape joints could be used in same service area. L-shape joints under static and fatigue loadings mostly indicated staple leg shear mode. The one under fatigue loading was more than the one under static loading. Additionally, some joints under fatigue loading indicated staple rupture. The overall ratio of static bending loading to cyclic fatigue bending loading for L-shape joints was obtained as 2.85. <![CDATA[Application of a strain gauge to assess drying stresses in normal and tension wood of <em>Corymbia citriodora</em>]]> Abstract: The quantitative evaluation of longitudinal drying strain can provide relevant information for the processing wood and lumber industry, especially with regard to reaction wood in Corymbia, since little has been published. The objective of this work was to evaluate the effect of the steam conditioning and the cooling on the longitudinal drying strain (LDS) obtained from a strain gauge, called extensometer, in boards of both normal and tension wood of Corymbia citriodora. Lumbers 30 mm thick were produced and kiln dried at the initial temperature of 40°C, final temperature of 65°C and drying potential of 2,1. The LDS were measured before and after steam conditioning on hot and cold lumbers. It was observed that the conditioning did not reduce the LDS. Hot lumbers showed higher LDS values than the cold lumbers. The LDS values measured in normal, tension and opposite woods were statistically similar, indicating that the type of wood was not an influential factor in the appearance of longitudinal drying stresses. Extensometer proved to be feasible for measuring LDS, allowing its easy and quick quantification. <![CDATA[Changes in the content and composition of the extractives in thermally modified tropical hardwoods]]> Abstract: Chemical composition of wood is known to change during thermal treatments. Two species grown in Turkey, afrormosia (Pericopsis elata) and duka (Tapirira guianensis) were heat treated according to Thermowood® method. Lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol and water were determined. Wood extracts were analysed by gas chromatography with mass detection and existing compounds were identified by NIST17 database. Results show that hemicelluloses and cellulose content decreased for both heat-treated woods along the treatment while lignin percentage increased. The analysis of extractives has shown several compounds normally associated to lignin thermal degradation that increased along the treatment. At the same time several compounds associated to carbohydrate thermal degradation were found in all the extracts for both heat-treated woods. These founding have allowed the understanding of the degradation pattern of wood during thermal modification. There was not much difference between afrormosia and duka woods structural compounds behaviour along thermal modification. However, the variation of the amount of extractives along the treatment depended on the species. <![CDATA[Mechanical and fire properties of oriental beech impregnated with fire-retardants and coated with polyurea/polyurethane hybrid and epoxy resins]]> Abstract: This study was performed to investigate some mechanical properties such as modulus of rupture and compression strength parallel to grain and some fire properties such as weight loss and temperature values of Oriental beech (Fagus orientalis) treated with fire-retardants and coated with polyurethane/polyurea hybrid resin and epoxy resin were investigated. The coatings are based on epoxy and polyurethane\polyurea hybrid resins. Firstly, an impregnation method was applied by using fire-retardants which are boron chemicals and ammonium sulfate before coating process. Oriental beech was impregnated with 3 % aqueous solution of boric acid, borax, boric acid and borax mixture (1:1), and ammonium sulfate. Oriental beech was primed with epoxy resin by using Sikafloor®-156, and then coated with Sikalastic®-851, a polyurethane/polyurea hybrid resin. Results showed that modulus of rupture and compression strength parallel to grain values of polyurethane/polyurea and epoxy resin coated Oriental beech wood were higher than that of un-treated and non-coated (control) group. Fire-retardants treatment before polyurethane/polyurea and epoxy resin coatings caused to decrease modulus of rupture and compression strength parallel to grain values of Oriental beech in some extent. Weight loss and temprature values of polyurethane/polyurea and epoxy resin coated Oriental beech were higher than that of un-treated and non-coated (control) group. Hovewer, fire-retardants treatment before polyurethane/polyurea and epoxy resin coatings improved fire properties of Oriental beech wood. <![CDATA[Combining artificial neural network and moth-flame optimization algorithm for optimization of ultrasound-assisted and microwave-assisted extraction parameters: Bark of <em>Pinus brutia</em>]]> Abstract: In this study, the extraction parameters of Pinus brutia bark were optimized using a hybrid artificial intelligence technique. Firstly, the bark samples were extracted by ultrasound-assisted extraction and microwave-assisted extraction which are defined as ‘green’ extraction methods at different conditions. The selected extraction parameters for ultrasound-assisted extraction were 0:100; 20:80; 40:60; 80:20 (%) ethanol: water ratios; 40 ºC, 60 °C extraction temperatures and 5 min, 10 min, 15 min, 20 min extraction times and for microwave-assisted extraction were 90, 180, 360, 600, 900 (W) microwave power, 0:100; 20:80; 40:60; 60:40; 80:20 (%) ethanol: water ratios. Then Stiasny number, condensed tannin content and reducing sugar content of all extracts were determined. Next, the prediction models were developed for each studied parameter using Artificial Neural Network. Finally, the extraction parameters were optimized using Moth-Flame Optimization Algorithm. After that optimization process, while the extraction time was the same (5 min), the ethanol: water ratio and extraction temperature values differed for the optimization of all studied assays of ultrasound-assisted extraction. Also, microwave power and ethanol: water ratio variables were found in different values for each assay of microwave-assisted extraction. The results showed that the Artificial Neural Network and Moth-Flame Optimization could be a novel and powerful hybrid approach to optimize the extraction parameters of Pinus brutia barks with saving time, cost, chemical and effort. <![CDATA[Lumber drying of <em>Pinus</em>: Geostatistics applied to drying kilns]]> Abstract: This study aimed to evaluate the spatial distribution of the air circulation speed and the final moisture content of pine lumber after kiln drying by using geostatistics. Two kilns acting on boards of 27 mm and 42 mm were evaluated. Air circulation speed and final moisture content were collected in different regions of the kilns. There was no significant difference for air circulation speed and final moisture content between the front and rear regions of the equipment. In the horizontal axis (Y-axis), air circulation speed averages did not differ statistically in both situations, but higher values for this variable were obtained from the spaces between the piles. Final moisture content tended to increase when closer to the door opening. In the vertical axis (Z-axis), the lower part tended to reach higher air circulation speed values. Thus, the spatial behavior influences the air circulation speed and final moisture content during lumber drying. Besides, the variograms presented the same tendency in comparison to the data obtained in a conventional manner, which indicates that geostatistics can be used to represent variables in kilns during the drying process. <![CDATA[Evolución del color y de la aparición de defectos en la madera de <em>Eucalyptus globulus</em> expuesta a intemperismo natural]]> Resumen: En el presente trabajo se evaluó el comportamiento de la madera de Eucalyptus globulus sin preservar, expuesta a la intemperie durante un año en la ciudad de La Plata, Argentina. Se analizó la evolución del color y la presencia de defectos, y su relación con algunas variables climáticas y con el contenido de humedad de la madera. Se colocaron 54 muestras (2,5 cm x 12 cm x 50 cm) en un expositor exterior con inclinación de 45º (norte) y sobre ellas se determinó mensualmente color (CIELab*), humedad y defectos. Una muestra sin exposición fue considerada testigo. Entre los 150-180 días de comenzar el ensayo, los parámetros L*, a* y b* alcanzaron valores cercanos al mínimo (49,22; -6,5; -1,90 respectivamente); al finalizar presentaron cambios significativos respecto a los valores iniciales (∆L*=22,55; ∆a*=5,41; ∆b*=16,64; ∆E*total=29,10) y al testigo. Los valores de radiación solar y precipitaciones no influyeron significativamente en el color mientras que la temperatura afectó al parámetro a*. El contenido de humedad de la madera se correlacionó con la presencia de algunos defectos, pero no afectó al color. El intemperismo provocó pérdida del color natural, adquiriendo un tono grisáceo (a* y b*cercanos a 0=acromático y L*=47,6) y aumentó el agrietado, siendo los primeros 150 días de exposición claves en este proceso.<hr/>Abstract: In this work, the behavior of Eucalyptus globulus unpreserved wood exposed outdoor for a year in La Plata city, Argentina, was evaluated. The evolution of color and defects presence were analyzed, and also their relationship with some climatic variables and the wood moisture content. Fifty-four samples (2.5 cm x 12 cm x 50 cm) were placed in an outdoor exhibitor with a 45º inclination (north), in which color (CIELab*), moisture content and defects were determined monthly. A sample without outdoor exposure was considered as control. After 150-180 days starting the test, the values of L*, a* and b* reached values close to the minimum (49.22; -6.5; -1.90, respectively). At the end, the colorimetric parameters showed significant changes with respect to the initial values (∆L*=22.55; ∆a*=5.41; ∆b*=16.64; ∆E*total=29.10) and to the control. The values of solar radiation and rainfall did not significantly influence the color, while the temperature affected the parameter a*. The moisture content of wood correlated with the presence of some defects, but it was not correlated with the color. Weathering caused loss of natural color, acquiring a grayish tone (a* and b* close to 0 = achromatic and L*=47.6) and increasing the level of cracking; the first 150 days of exposure were key in this process. <![CDATA[The effects of bioincising by <em>Physisporinus vitreus</em> on cuo retention and copper element leaching in oriental spruce wood]]> Abstract: Since the treatability of Oriental spruce wood (Picea orientalis) with preservative solutions is difficult and considered as a refractory wood species, this study was intended to bring its treatability class by a bioincising process to the level of sapwood of Scots pine (Pinus sylvestris), a desirable wood species for the forest products industry. Bioincising process by Physisporinus vitreus fungus was applied to wood samples from sapwood and heartwood portions of spruce wood. The samples with two different weight loss groups (5-10 % and 10-15 %) in the bioincising process were used to detect changes in treatability with wood preservative solutions caused by the fungus. The bioincised and unincised control samples were treated with either micronized copper quat (MCQ) or alkaline copper quat type D (ACQ-D) wood preservative solutions by either dipping or vacuum methods. Following impregnation with the preservative solutions, the effects of the bioincising process on CuO (copper oxide) retention, and the leaching of Cu (copper) element were determined. The results showed that CuO retention levels increased after the bioincising process. Moreover, there was greater CuO retention in the spruce heartwood samples compared to the spruce and Scots pine sapwood samples. Amount of Cu element released from the Scots pine sapwood samples was found to be lower than that from the spruce sapwood and heartwood samples after the bioincising. process. The results suggest that the bioincising process by P. vitreus in refractory wood species might improve the treatability of wood by Cu-based wood preservatives. <![CDATA[Properties of gypsum particleboard with added mineral dolomite]]> Abstract: Red pine (Pinus brutia) wood particles and dolomite mineral were used in varying proportions to form mineral-added gypsum particleboards. Mechanical, physical, and chemical properties of the boards were tested. The increasing mineral content was found to improve the water absorption properties but the increased amount of gypsum in the mixture negatively affected the thickness swelling and water absorption properties. The usage of dolomite mineral in the board composition increased the internal bond properties and higher than the standard of 0,28 MPa. However, all types of boards had modulus of elastic, modulus of rupture and thermal conductivity results values below the standards. Moreover, the thermal conductivity values decreased in all board types because of the reduction of the mineral dolomite. Thermal gravimetric analysis, Fourier transform infrared spectrometry tests were applied to examine the thermal and flame retardancy properties of inorganic materials, wood-gypsum composites, which are used at different rates for synergistic effect. The gypsum and dolomite amount affected the thermal variation, whereas the increment in the weight of the wood particles also increased the thermal degradation. It was determined that stresses at 850-980 cm-1 reveal Ca-O and Mg-O, reveal at 881cm-1 C-OH, weak vibration at 1619 cm-1 and a strong bond structure in the 1445-950-882 cm-1 bands. These bands express the characteristic presence of the CaO and MgO belonging to dolomite. The study demonstrated the feasibility of producing mineral-based gypsum board products using wood chips. <![CDATA[Shear strength and hardness of two tropical wood species as function of heat treatment]]> Abstract: The aim of this study was to evaluate the effect of heat treatment on surface roughness, shear strength and hardness of two tropical wood species, namely batai (Paraserainthes falcataria) and sesendok (Endospermum malaccensis). Samples were exposed to temperature levels of 120 ºC and 180 ºC for 3 h and 6 h. The surface quality of the control and heat-treated samples were determined using a stylus technique. Hardness and shear strength of the samples were evaluated using Janka hardness and block-shear test, respectively. The results reveal that the surface roughness of batai improved 3 % for 80-grit and 5 % for 180-grit samples while surface roughness of sesendok improved 7 % and 10 % for 80-grit and 180-grit, respectively by the increase of the heat temperature and prolonged durations. Analysis of variance (ANOVA) also revealed that most of the tested properties on the treated wood were significantly affected by the species, girt number and also temperature. In contrast to the untreated wood species, the heat-treated wood species exhibited lower values of shear strength and hardness. Overall, the hardness and shear of both species were adversely influenced by heat exposure. <![CDATA[Wettability and decay of particleboards manufactured with thermally treated sugarcane residue and bamboo (<em>Dendrocalamus asper</em>) particles]]> Abstract: This study aimed to evaluate the chemical composition of wood particles (control and treated), and the effects of thermal modification and adhesive levels on the wettability and biological resistance of particleboards made of sugarcane residue and bamboo (Dendrocalamus asper). Therefore, 75% bamboo particles and 25% sugarcane residue (bagasse) were used for producing the particleboards. The particles were treated at 220 °C for 3h35min. Urea formaldehyde (UF) adhesive was used in three solid contents (10%, 12% and 14%) based on the dry mass of the particles. The mat was cold pre-consolidated (pressure of 0,5 MPa for 5 min) and after hot consolidated (3,45 MPa, 180 ºC, 10 min). Water and ethylene glycol and two measurement times were used to measure the contact angle. Gloeophyllum trabeum and Rhodonia placenta (brown rot) and Trametes versicolor (white rot) fungi were used for the biological resistance test. There was a change in the chemical composition of the treated particles such as a reduction in the levels of lignin (bagasse and bamboo), total extracts and holocellulose (bagasse). The thermal treatment increased the final contact angles obtained with water. The particleboard surfaces were classified as non-wettable and partially wettable to the tested solvents. The thermal treatment provided biological resistance improvements in the particleboards to the tested fungi, being classified as very resistant to Rhodonia placenta, resistant to very resistant to Gloeophyllum trabeum, and moderate to resistant to Trametes versicolor. <![CDATA[Weight-strength optimization of wooden household chairs based on member section size]]> Abstract: Weight-strength optimization of wooden household chairs was performed based on the member section size in this study. Member section sizes of the Scotch pine (Pinus sylvestris) and Oriental beech (Fagus orientalis) chairs were optimized and resulting re-manufactured optimized chairs were tested under the cyclic “front to back”, “back to front” and “backrest” loads according to American Library Association (ALA) specification. Finite element method (FEM) and MATLAB nonlinear programming were utilized for the optimization. Firstly, the internal forces and moments acting on each member were analyzed by FEM in order to obtain the maximum critical stresses in each type of member; then, optimized cross-sectional sizes of the members were determined by Gradient Descent method, and all constraints were treated with Logarithmic Barrier Functioning. As a result, the minimum section sizes of members were determined, and cyclic performance tests were performed to determine whether the optimized chairs were strong enough to carry the acceptable loads. According to the results, member section size of both beech and pine chairs could be significantly reduced. The reduction was 32 % in the total weight and volume for beech chairs while 16 % for pine chairs without sacrificing the performance required for domestic usage by ALA. In conclusion, the method used is suitable for the optimization of furniture frames, making it lighter and reducing the material costs. <![CDATA[Colorimetría y densitometría en madera de <em>Guazuma crinita</em>]]> Resumen: En el presente trabajo se determinaron los parámetros colorimétricos mediante el sistema CIELAB y la densidad aparente por densitometría de rayos X en madera de Guazuma crinita para obtener información de su calidad en el uso como madera solida o transformada. La evaluación se realizó en tres niveles del eje axial (basal, medio y apical) de una plantación de 5 y 8 años, en la zona de Puerto Inca, departamento de Huánuco, Perú. En ambas edades, empleando el sistema CIElab, se encontró que la madera es de coloración homogénea y se clasifica como rosa grisáceo. La densidad aparente medida por densitometría de rayos X en el sentido médula - corteza fue de 520 kg/m3 y 560 kg/m3 para 5 y 8 años respectivamente; con promedios mayores en el nivel basal (5 años: 650 kg/m3; 8 años:680 kg/m3) y menores en el nivel apical (5 años: 430 kg/m3; 8 años: 470 kg/m3). Los perfiles densitométricos mostraron, en general, que radialmente hay un aumento de la densidad aparente en el sentido médula - corteza. La densidad de la madera madera de 5 años resultó más uniforme que la de 8 años con un índice de uniformidad de 149,7 y 170,3, respectivamente.<hr/>Abstract: In the present work, the colorimetric parameters were determined using the CIELAB system and the apparent density by X-ray densitometry in Guazuma crinita Mart. wood to obtain information of its quality in use as solid or transformed wood. The evaluation was carried out in three levels of the axial axis (base, medium, apical) of one plantation of 5 and 8 years old, in Puerto Inca, department of Huánuco, Peru. It was found that in both ages, according to CIElab system, the wood is of homogeneous coloration and is classified as greyish pink. The apparent density measured by X ray densitometry in the pith - bark direction was found to be 520 kg/m3 and 560 kg/m3 for 5 and 8 years, respectively; with higher values at the basal level (5 years old: 650 kg/m3; 8 years old: 680 kg/m3) and lower towards the apical part (5 years old: 430 kg/m3; 8 years old: 470 kg/m3). The densitometric profiles showed, in general, that there is an increase in apparent density radially in the pith-bark direction. The 5-year-old wood density was more uniform than the 8-year-old one with a uniformity index of 149,7 and 170,3, respectively. <![CDATA[Formaldehyde free tannin-based adhesive with epoxy as hardener for plywood]]> Abstract: A renewable tannin-based resin adhesive with enhanced bonding strength, good water resistance and long storage life has been prepared based on tannin, furfural and furfuryl alcohol coming from forest and agricultural products. Fourier transform infrared spectroscopy (FT-IR), Electrospray ionization mass spectroscopy (ESI-MS) and Differential scanning calorimetry (DSC) indicated that furfuryl alcohol and furfural can react with tannin under acidic conditions, with the involvement of -CH2-O- groups in the cross-linking of tannin-furfuryl alcohol-furfural resin (TFF) adhesive. The gel time of TFF was longer than that of tannin-furfural resin (TF), while the shear strength of TFF-bonded plywood suggested that the cured TFF adhesive acquired a performance superior to that of tannin (T) and TF adhesives. Furthermore, water resistance of TFF adhesive could be further enhanced with respect to T and TF adhesives through cross-linking with 3 % epoxy resin (EPR). <![CDATA[Effect of borax-boric acid and ammonium polyphosphate on flame retardancy of natural fiber polyethylene composites]]> Abstract: Wood fiber filled high density polyethylene composites (WPCs) were prepared using twin screw extruder and maleated polyethylene as a coupling agent. Bamboo fibers were initially treated with alkali (NaOH), boric acid - borax (Ba-Bx) and borax (Bx). The treated and untreated fibers were used in combination with ammonium polyphosphate (APP) to investigate their synergistic effects on thermal stability, flame retardancy and mechanical properties. Alkali pretreatment (5 % NaOH) of fibers showed significant improvement in performance of APP by increasing thermal stability in WPCs. The derivative thermogravimetric (DTG) results indicate significance of Ba-Bx in promoting char induction at lower temperatures (340 ºC) and thereby, improved the thermal stability in WPCs. Flammability decreased with addition of flame retardant additives. As compared to pure WPCs, composites containing APP 10 % / Ba-Bx 5 % exhibited maximum reduction in average heat release rate (HRR) by 69 %, peak heat release rate (PHRR) by 59 %, total heat released rate (THR) by 48 % and also increased time to ignition (TTI) by 62 %. However, no significant difference was found among the combinations i.e., APP with or without compounds towards reducing the flammability of WPCs. The strength properties also reduced significantly when boron compounds were added along with APP. In general, APP alone (15 %) is enough for imparting thermal stability and flame retardancy in WPCs. <![CDATA[Evaluation of mycelium composite materials produced by five Patagonian fungal species]]> Abstract: Mycelium composites consist of particulate lignocellulosic materials, e.g., sawdust from the timber industry structured as a solid matrix resulting from the mycelial growth. Many protocols have been proposed based on different strains and substrates. However, the influence of intrinsic elements, such as the structure of the hyphal system on the main parameters required by the industry still needs to be researched. The main goal of this work is to assess the performance of five Patagonian lignocellulolytic fungal species for producing mycelium composites. Strains of these species were studied in order to assess the relation between basidiome hyphal structure and the hyphal structure of mycelium-based materials. Comparisons of the hardness in the Janka scale were performed with commercial expanded polystyrene. Composites resulting from the growth of Pleurotus ostreatus, Nothophellinus andinopatagonicus and Funalia trogii successfully formed composites, showing a lower quality than Ganoderma austral. Ryvardenia cretacea in turn completely failed to colonize the substrate. The material resulting from the growth of Ganoderma australe on pine sawdust (a substrate chosen based on its local availability) is proposed as a good substitute with improved resistance. <![CDATA[Predictive expressions for withdrawal force capacity of various size of dowels from particleboard and medium density fiberboard]]> Abstract: The objective of this study was to develop predictive expressions for estimating the withdrawal force capacity of various size of beech (Fagus orientalis) dowels from medium density fiberboard (MDF) and particleboard (PB). Furthermore, effects of the base material type, dowel diameter, dowel penetration and adhesive type on withdrawal force capacity were investigated. Polyurethane (PU), polyvinyl acetate based D2, and polyvinyl acetate (PVA) adhesives were utilized for gluing of dowels. A total of 540 specimens were prepared for edge and face withdrawal force capacity tests including two material types (MDF, PB), three dowel diameters (6 mm, 8 mm, 10 mm), three dowel penetration depths (15 mm, 20 mm, 25 mm for edge, 6 mm, 9 mm, 12 mm for face), three adhesive types and five replications for each group. Specimens were tested under static withdrawal forces. Based on results of tests, predictive expressions that allow furniture engineers to estimate edge and face dowel withdrawal force capacity as a function of dowel diameter and dowel penetration were developed. Calculations showed that the expressions developed provided reasonable estimates for withdrawal force capacity of dowels. As a result of statistical analyses, material type, dowel diameter, dowel penetration, adhesive type and their four-way interaction have significantly affected the withdrawal force capacity of dowels. Test results also indicated that PU adhesive and MDF ranked the highest withdrawal force capacity among the adhesive and material types. Increasing either dowel diameter or penetration tended to have a positive effect on withdrawal force capacity. Dowel diameter was found to have a higher effect on withdrawal force capacity than dowel penetration. <![CDATA[Antifungal and larvicidal effects of wood vinegar on wood-destroying fungi and insects]]> Abstract: Wood vinegar is a natural organic pesticide that is effective against plant diseases and harmful insects and is used in agriculture in particular for the improvement of plant and soil quality.In different application areas, wood vinegar provides effective protection against various harmful bacteria, fungi, and insects.Based on its demonstrated protection as a pesticide and antifungal, this study aimed to use wood vinegar as an impregnation agent in wood materials. For this purpose, using the full-cell process, Pinus sylvestris and Fagus orientalis samples were impregnated with concentrations of 1 %, 5 %, 3 % and 6% oak wood vinegar, obtained via the pyrolysis of sessile Quercus petraea. wood at 350 °C.The samples were then subjected to tests for brown-rot (Serpula lacrymans) and white-rot (Trametes versicolor) fungi, for Hylotrupes bajulus (Coleoptera: Cerambycidae) larvae, and for three different mold fungi (Aspergillus niger Tiegh JAG-04-1003, Penicillium brevicompactum Dierckx FS-31, and Trichoderma harzianum Rifai FS-19). According to the results, the wood vinegar was found to exhibit antifungal, antimold, and larvicidal properties and consequently, could be used effectively in wood protection. <![CDATA[Chemical variations in tension wood of poplar tree induced by intermittent bending, fertilizer and hormone treatments]]> Abstract: Tree growth is influenced by various environmental factors that lead to anatomical, physical and chemical changes in their wood. Reaction wood is one of the tree's reactions that make many restrictions in wood usages. Reaction wood in broadleaf is called tension wood. This study was aimed to stimulate the formation of tension wood in two-year-old seedlings of Populus alba by using intermittent bending, nitrogen fertilization and gibberellin hormone. The application of different treatments increased the content of cellulose compared to the control sample. Meanwhile, the bent specimens had more increase while the straight specimens had no significant difference in the statistical grouping. The content of lignin decreased in all treatments compared to the control sample. The cellulose/lignin ratios obtained from ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared) analysis of wood sawdust and chemical composition measurements were almost close to each other and were higher in the treated samples than in the control. The degree of crystallinity obtained from XRD (X-ray Diffraction) measurements showed that all samples under intermittent bending had a significantly higher degree of crystallinity than the control sample, while this increase was not significant in all straight samples compared to the control sample. In general, it can be concluded that intermittent bending treatment had a greater effect on the stimulation and changes of chemical properties of tension wood in poplar and the application of nitrogen fertilization and gibberellin hormone increased this effect. The formation of gelatinous layer in the innermost part of the intermittent bent seedlings fiber cell wall was visible in light microscope images. <![CDATA[Investigations on the sorption behaviour of selected wood species from Cameroon]]> Abstract: The sorption isotherms during adsorption and desorption of 25 wood species from Cameroon (included 3 species from plantation in Togo) were determined. In addition, the chemical compositions of these wood species were tested. The equilibrium moisture contents in a normal climate varied between 10,55% and 15,6%. A clear influence of the proportion of extractives can be seen. The maximum differences between adsorption and desorption varied between 2,3% and 3,6%. <![CDATA[Exploratory studies on effects of growth location and conditioning on treatability and permeability of southern pine lumber]]> Abstract: Southern pine lumber is often treated with preservatives, but issues related to initial kiln-drying conditions and geographic source across the wide southern pine growth range have been suspected to negatively affect subsequent permeability and treatability. These effects remain poorly understood. In this series of exploratory studies, southern pine from across part of the growing range subjected to different kiln-drying regimes was evaluated in three phases exploring the effects of geographic source and initial kiln-drying conditions on permeability, pit structure and eventual preservative treatment of southern pine lumber. The results suggest that elevated temperatures coupled with poor humidity control at the start of the kiln drying process may negatively influence permeability and preservative penetration, but had only negligible effects on several other wood properties. <![CDATA[Prediction of surface roughness of CO<sub>2</sub> laser modified poplar wood via response surface methodology]]> Abstract: Due to the advantages of short treatment period, no wastewater and oil produced, the CO2 laser is applied as an environment friendly thermal treatment for wood materials to improve the wood properties, such as appearance, color and wettability, among others. However, the morphological features of treated wood surface are also changed, which have negative effects on wooden product properties. To reveal the change tendency of surface roughness during laser irradiation, the common indexes of average roughness (Ra) and mean peak-to-valley height (Rz) were chosen to evaluate the surface roughness. The response surface methodology was selected to arrange the experiments and analyze the influences of laser parameters on surface roughness. The results showed that the poplar wood got rougher with the increased laser power, but the surface roughness decreased with increased feed speed and path spacing, due to the total heat absorption varied under different combination of laser parameters. The ANOVA results showed that the selected quadratic models for Ra∥, Rz∥, Ra⊥and Rz⊥were significant due to the values of probability value (“Prob&gt;F”) less than 0,05. In this case, all the input laser parameters were also the significant model terms for variation of surface roughness. The values of correlation coefficient were very close to 1, which meant the selected quadratic models could give accurate prediction of surface roughness for laser treated wood. Therefore, it is of great significance to predict the surface roughness of the modified wood surface scientifically and to guide the selection of reasonable modification process parameters. <![CDATA[Caracterización morfológica de las traqueidas de pino híbrido de rápido crecimiento]]> Resumen: El objetivo de este trabajo fue evaluar la variación radial de la morfología de las traqueidas de pinos híbridos. Se extrajeron tarugos radiales de árboles de pino híbrido “F1 INTA-PINDO”, en dos ensayos. Las muestras se tomaron a 1,30 m de altura, se disociaron y se midieron las características anatómicas de las traqueidas individuales obtenidas de la fracción de madera tardía de los anillos de crecimiento 4, 7, 10 y 11 mediante microscopía óptica con análisis de imagen. Para la obtención del ángulo microfibrilar se utilizó la técnica a través de las puntuaciones en traqueidas individuales. Para el ángulo microfibrilar dentro de cada edad, se encontraron diferencias estadísticas significativas entre sitios y familias para un nivel de confianza del 95 %, mientras que las variaciones no fueron significativas para las demás propiedades estudiadas. Se observaron cambios importantes en la morfología celular de las traqueidas para las edades consideradas. Los valores medios de ángulo microfibrilar, ancho del lumen y ancho total de las traqueidas disminuyeron con la edad, independientemente del sitio y las familias evaluadas. Los valores medios de espesor y la proporción de pared celular aumentaron con la edad. Estos resultados indican que las propiedades de la madera no serían uniformes en el sentido radial y deben ser tenidas en cuenta al momento de utilizarlas para determinados usos. Se identificaron familias con mejor performance en crecimiento y parámetros deseables para la calidad estructural de la madera, las mismas pertenecen a las mejores posiciones del ranking genético de crecimiento. Se concluye que, a los 11 años de edad este taxón produce madera madura, debido a las características de su morfología celular.<hr/>Abstract: This work aimed to evaluate radial variation of tracheid morphology for hybrid pines. Radial increments cores were extracted from trees of hybrid pine “F1 INTA-PINDO” in two trials. The samples were taken at 1,30 m in height, they were dissociated, and the anatomical characteristics of individual tracheids obtained from the latewood fraction of growth rings 4, 7, 10, and 11 were measured by optical microscopy with image analysis. To obtain the microfibrillar angle, the technique "through individual tracheid pit apertures" was used. For microfibrillar angle within each age, significant statistical differences were found between sites and families for a confidence level of 95%, whereas the variations were not significant for others studied properties. Important changes with considered ages were observed in the cell morphology of the tracheids. The mean values of microfibrillar angle, lumen width, and the total width of tracheids decreased with age, regardless of sites and evaluated families. The mean values of cell wall-thickness and cell-wall ratio increased with age. These results indicate that wood properties would not be uniform in the radial direction and they must be taken into account for certain uses. Families with better growth performance and desirable parameters for structural wood quality were identified. The outstanding families belong to the best positions of growth genetic ranking. It is concluded that at 11 years old, this taxon produces mature wood, due to the characteristics of its cell morphology. <![CDATA[Performance of cement-bonded wood particleboards produced using fly ash and spruce planer shavings]]> Abstract: The aim of this research was to investigate the physico-mechanical, thermal, and morphological properties of cement-bonded wood particleboards produced by using fly as has a partial cement replacement and spruce planer shavings. Experimental single-layer cement-bonded wood particleboards produced using a target density of 1200 kg/m3, 1/3 wood-cement ratio, a dimension of 460x460x10 mm3 and 5%, 10%, 15%, 20% fly ash as cement replacement were tested for physical and mechanical properties in accordance with EN and ASTM standards. Moreover, morphological and thermal properties of the cement-bonded wood particleboards were analysed by using the scanning electron microscope and thermogravimetric analysis-derivative thermogravimetry. Test results indicated that the fly ash enhanced both the bending strength and water-resistance of the cement-bonded wood particleboards. Internal bond and screw withdrawal strengths tended to decrease as the fly ash content increased in the cement-bonded wood particleboards, but this decrease was not statistically significant. As the fly ash increased, the weight loss of the cement-bonded wood particleboards decreased in the thermogravimetric analysis because of the pozzolonic reaction of the fly ash with calcium hydroxide. In the scanning electron microscope, it was observed that calcium silicate hydrate gel increased, whereas calcium hydroxide decreased as the usageratio of the fly ash increased in the cement-bonded wood particleboards. <![CDATA[Carbon footprint of wooden and plastic pallets: A quantification with different software tools]]> Abstract: Transport is one of the activities that generates the highest CO2 eq emissions. In the particular case of Chile, it is the second economic activity that generates the greatest environmental impact. The safe and efficient transport of products in domestic and foreign markets is often carried out with the help of pallets made of various materials, such as wood or plastic, which goes hand in hand with different environmental performance in their production. That is why it is important to know the carbon footprint of these products. The objectives of this study are to compare the value of the carbon footprint generated by the local production of wooden and plastic pallets and to evaluate the variations in its quantification using different software. For this purpose, the Chilean market is taken as a reference. This study follows the main guidelines of ISO standards as a reference framework. The functional unit is 1 pallet produced and the system boundary is from cradle to gate. The results show that wood and plastic pallets have an average carbon footprint of 4,12 kg CO2 eq and 38,85 kg CO2 eq respectively. The difference between the two pallets is mainly due to the environmental load of the raw materials. The causes of the variation in the estimation of the carbon footprint with different software are specifically based on the databases with which they can work. The ratio of 1:9 between the carbon footprint of wooden pallets concerning plastic pallets provides important data for decision making. <![CDATA[Comparison of thermal performances of plywood shear walls produced with different thermal insulation materials]]> Abstract: Shear walls are one of the envelopes of light-frame wooden buildings where thermal insulation is most required. The thermal performance of shear walls can vary according to the type, properties and thickness of the wood and insulation materials used in their production. This study, it was aimed to compare the thermal performances of plywood shear walls produced with different thermal insulation materials. For this aim, the archetype walls with properties similar to commonly used plywood shear walls were designed and produced for each thermal insulation material type and wood specie. The shear wall groups were formed by using Scots pine (Pinus sylvestris), black pine (Pinus nigra) and spruce (Picea orientalis) as wood species and cellulose, flax, felt, XPS, EPS, sheep’s, rock and glass wool as thermal insulation materials. The thermal conductivity of the shear wall groups was determined according to the standard. Thermal resistance and other thermal performance parameters were calculated using the thermal conductivity values. As a result of the study, rock wool was the best thermal insulation material among the Scots pine shear wall groups while glass wool was the best thermal insulation material among the black pine and spruce shear wall groups. The shear walls produced with EPS foam boards indicated the worst thermal performance among all groups. <![CDATA[Chemical constituents of palm wastes slow pyrolysis derived vinegar]]> Abstract Out of rachis and stem of palm tree from grooves in humid and dry zones, test materials were randomly collected and chipped for slow pyrolysis process. Chemical constituents of a set of pyrolysis derived vinegar were identified in their aqueous phase by gas chromatograph and quantitatively compared in sampled parts of sampled tree and grooves. Another set of vinegar was dewatered by dichloromethane, then their constituents were identified by gas chromatograph coupled with mass spectrometer, chemical constituents in aqueous state in both sampled grooves were the same but with different percentage values. In the organic phase, common chemical constituents of sampled parts and grooves were quantitatively compared. In humid zone rachis was 2,22 times richer in acetic acid and 2,37 times in phenol, but in dry zone stem is richer in acetic acid by 15,35 %. In their organic phases dominant and comparable chemicals of stem and rachis from sampled zone were furfural, phenol, benzic acid, 5-methyl-2- furancarboraldehyde, butanic acid and 2-methyl-phenol. Stem from dry zone was richer in these chemicals by 36,55 %; 96,93 %; 6,37 times, 62,05; 49; 32,57 % respectively. Rachis of humid zone contained more furfural, 63,95 %, 22,08 %, 2-methyl-phenol, but that of dry zone was richer in phenol by 46,20 %, 2,5 times in benzoic acid. Results from both phases of vinegar indicate that ecological impacts on the chemical constituents of palm from the same species are evident. <![CDATA[Efecto del ángulo microfibrilar en las características tecnológicas de la madera de <em>Pinus pseudostrobus</em> var. <em>apulcensis</em>]]> Resumen: El ángulo microfibrilar es la inclinación de las microfibrillas de celulosa en la pared celular en relación al eje vertical de la célula. Esta característica contribuye en explicar las variaciones en propiedades físicas y mecánicas de la madera y fibra procesada. Pinus pseudostrobus var. apulcensis es una especie forestal nativa de México con importancia económica e industrial. Se seleccionaron al azar 10 árboles sanos de esta especie en una plantación en Texcoco, Estado de México, México. De cada árbol se extrajo un tarugo a 1,3 m de altura de fuste. Se midió el ángulo microfibrilar, la densidad básica (DB), la longitud de traqueidas y la contracción volumétrica con el objetivo de determinar el efecto del ángulo microfibrilar sobre dichas características tecnológicas en esta madera. Se obtuvo un ángulo microfibrilar promedio de 28,8°; densidad básica promedio de 430 kg/m3; longitud de traqueidas promedio de 3516 µm y contracción volumétrica promedio de 10,3 %. Se ajustaron modelos aditivos generalizados entre el ángulo microfibrilar como variable explicativa y cada una de las tres variables respuesta por separado. Finalmente se ajustó un modelo aditivo generalizado para conocer el comportamiento de la densidad básica, longitud de traqueidas y contracción volumétrica en función del ángulo microfibrilar. Este modelo generado tuvo una capacidad explicativa de 88,2 %. La variable mejor explicada por el ángulo microfibrilar fue la longitud de traqueidas (capacidad explicativa de 83,3 %). Sería interesante observar si este comportamiento se presenta en otras especies de pino mexicanas.<hr/>Abstract: Microfibril angle (MFA) is the inclination of the cellulose microfibrils within the cell wall relative to the vertical axis of the cell. This characteristic contributes to explaining the variations in the physical and mechanical properties of processed wood and fiber. Pinus pseudostrobus var. apulcensis is a forest species native to Mexico with great economic and industrial importance. 10 healthy trees of this species were randomly selected on a plantation in Texcoco, Mexico, and from each tree a core was extracted at 1,30 m stem height. Microfibril angle, basic density (BD), tracheid length (TL) and volumetric contraction (VC) were measured in order to determine the effect of MFA on said technological characteristics in this wood. An average MFA of 28,8 ° was obtained; Average BD of 430 kg/m3; Average TL of 3516 µm and an average VC of 10,3 %. Generalized additive models (GAM) were adjusted between the MFA as the explanatory variable and each of the three response variables separately. Finally, a generalized additive model was adjusted to know the behavior of BD, TL and VC as a function of MFA. This generated model had an explanatory capacity of 88,2 %. The best explained variable by MFA was TL (explanatory capacity of 83,3 %). It would be interesting to see if this behavior occurs in other Mexican pine species. <![CDATA[Analysis of biochars produced from the gasification of <em>Pinus patula</em> pellets and chips as soil amendments]]> Abstract: In this work, biochar (BC), a co-product of the fixed bed gasification process of Pinus patula wood pellets (PL) and chips (CH), was characterized as soil amendment. The physicochemical properties and the mineral content of the pellet’s biochar (PL-BC) and the chips biochar (CH-BC) were analyzed following the NTC5167 Colombian technical standard. The BET surface area values of the BCs were 367,33 m2/g and 233,56 m2/g for the PL-BC and the CH-BC, respectively, and the pore volume was 0,20 cm3/g for the PL-BC and 0,13 cm3/g for the CH-BC. These characteristics favor the increase of the BCs water-holding capacity (WHC). Properties such as the pH (8,8-9,0), the WHC (219 %-186,4 %), the total organic carbon (33,8 %-23,9 %), the metalloid presence (Ca, Mg, K, Mn, Al, Si, and Fe), and the ash (1,92wt % - 2,74 wt %) and moisture contents (11,13wt %-11,63 wt %) for both BCs were found to be within the limits set by the standard. Furthermore, the presence of micro and macronutrients, such as Fe and phosphorus (P), and the alkaline pH, make possible the use of these BCs as amendments for acid soils. <![CDATA[Deep eutectic solvent pulping from sorghum stalks]]> Abstract: Deep eutectic solvents are characterized as natural, green, biodegradable, non-flammable, non-volatile, non-toxic, odorless, colorless, easy to prepare, and easy to recycle after use. They present an opportunity to introduce new techniques for the pulping process. This study investigated the possibility of using a green deep eutectic solvents from sorghum stalks for pulp and paper production. Choline chloride/ethylene glycol was used in the preparation of eutectic mixtures in molar ratios of 4/10, 5/10, and 6/10. These eutectic mixtures were then applied as cooking liquor to sorghum stalks at two different cooking times (140 and 160 minutes). In addition, the traditional pulping methods of soda and kraft cookings were carried out using sorghum stalks and the pulps were compared with the deep eutectic solvents pulps. The results showed that the pulp production using deep eutectic solvents was accomplished successfully. Some properties of deep eutectic solvents pulps were comparable to those of the soda and kraft pulps. deep eutectic solvents can play an essential role in cleaner pulp production. <![CDATA[Natural durability of five tropical wood species in field decay tests]]> Abstract: Measuring the natural resistance of wood is fundamental for proper use. The natural durability of five tropical wood species was investigated by field decay testing during exposure for 360 days. Wood logs (length of 0,5 m; diameter of 8 cm - 12 cm) were used in this study. The mass loss and decay index were calculated and visual analysis during the exposure time was performed for all samples. The samples presented evidence of two different groups concerning natural durability. The species in the first group (Mimosa caesalpiniifolia, Mimosa ophthalmocentra, and Mimosa tenuiflora) showed the highest resistance to biodeterioration, better or similar performance compared to treated Eucalypts wood (as control). The other group (Aspidosperma pyrifolium and Cordia oncocalyx) had lower natural resistance in outdoor service, being more susceptible to decay. In general, the wood of the first group is indicated for outdoor uses that require medium or prolonged exposure, such as timber stakes and fence posts. <![CDATA[Changing the calculated surface area of wood samples to define drying schedules for <em>Eucalyptus</em> clones]]> Abstract: The aim of this study was to determine how varying the inputted surface area value of wood samples would affect the determination of kiln-drying schedules using the drastic drying test. For this purpose, eight individuals of two Eucalyptus clones were selected. Specimens were obtained for drastic drying tests at 100 °C, to measure the basic density and to determine the initial moisture content. The initial and final temperatures and the drying potential were calculated in 100 mm × 50 mm × 10 mm samples, considering the surface area to be 130 cm² (Updated Method), in contrast to the surface area of 100 cm² that is commonly used in the method known as the Standard Method. Based on these findings, kiln-drying schedules were set for the lumber from each clone. Although the significant differences aforementioned, it was observed that the drying schedules developed by Standard Method and Updated Method are similar. <![CDATA[Preliminary evaluation of the incorporation of cellulose nanofibers as reinforcement in waterborne wood coatings]]> Abstract: The wood is exposed to possible damages caused by weather, requiring the application of a finishing coat to provide extra protection. The aim of this work was to evaluate the influence of the addition of microfibrillated cellulose in waterborne varnish on the colorimetric parameters, wettability and finish characteristics of wood products. Color was evaluated with a CM-5 spectrophotometer; surface wettability was analyzed by contact angle measurement using a drop shape analysis goniometer; and abrasion, adhesion and impact tests were performed to evaluate the quality of the coating. The coating’s optical characteristics were not affected by the addition of microfibrillated cellulose. The changes in wood wettability were small, with no statistical difference between the wood treated with plain varnish and that with unbleached microfibrillated cellulose. In the analysis of the variation of the contact angle during the elapsed time, the coating containing unbleached microfibrillated cellulose presented the best results. The results of finish quality did not show numerical changes after the addition of the microfibrillated cellulose, but qualitatively the microfibrillated cellulose caused better anchoring of the coating to the specimens. Therefore, the use of microfibrillated cellulose as reinforcement in coatings has potential, but tests with different consistencies and tests of other properties are necessary. <![CDATA[Characterization of <em>Acrocarpus fraxinifolius</em> wood submitted to heat treatment]]> Abstract: Aiming to provide greater visibility for the wood species Acrocarpus fraxinifolius, the present study sought to analyze the influence of heat treatment on an industrial scale applied to wood species, also popularly known as Indian cedar. The heat treatment was carried out in an autoclave, with temperature and pressure control, and with saturated steam injection, for temperatures 155 ºC, 165 ºC, 175 ºC, and 185 ºC. Physical, chemical, and mechanical tests were carried out for the analyzed wood. The content of holocellulose and total lignin decreased, while the content of extractives showed a substantial increase. The density increased after the heat treatment, however the treated wood showed cracks, and these cracks influenced the significant loss of the values of the mechanical properties of compression, tension, and flexion. The shear showed strength gain for the temperature of 155 ºC, and the wood treated at 165 ºC was equivalent to untreated wood. The woods submitted to temperatures of 175 ºC and 185 ºC presented strength losses. The heat treatment in question contributes to increase the visibility, use and market value of wood. <![CDATA[Erratum]]> Abstract: Aiming to provide greater visibility for the wood species Acrocarpus fraxinifolius, the present study sought to analyze the influence of heat treatment on an industrial scale applied to wood species, also popularly known as Indian cedar. The heat treatment was carried out in an autoclave, with temperature and pressure control, and with saturated steam injection, for temperatures 155 ºC, 165 ºC, 175 ºC, and 185 ºC. Physical, chemical, and mechanical tests were carried out for the analyzed wood. The content of holocellulose and total lignin decreased, while the content of extractives showed a substantial increase. The density increased after the heat treatment, however the treated wood showed cracks, and these cracks influenced the significant loss of the values of the mechanical properties of compression, tension, and flexion. The shear showed strength gain for the temperature of 155 ºC, and the wood treated at 165 ºC was equivalent to untreated wood. The woods submitted to temperatures of 175 ºC and 185 ºC presented strength losses. The heat treatment in question contributes to increase the visibility, use and market value of wood.