Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

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.

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 %.

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 0,43 g·cm-3; 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.

Transport is one of the activities that generates the highest CO2eq 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 14040 and ISO 14067 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 CO2eq and 38,85 kg CO2eq 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.

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 (1,92 wt% - 2,74 wt%) and moisture contents (11,13 wt% - 11,63 wt%) for both BCs were found to be within the limits set by the NTC5167 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.

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. In 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. Thermal conductivity of the shear wall groups was determined according to the ASTM C518-04 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

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.

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.

The aim of this research was to investigate the physico-mechanical, thermal, and morphological properties of cement-bonded wood particleboards produced by using fly ash as 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 460 x 460 x 10 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 usage ratio of the fly ash increased in the cement-bonded wood particleboards.

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 eucalyptus 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.