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.

ABSTRACT This research aimed at evaluating the quality of bonded joints of Eucalyptus wood by using different faces and adhesives to produce EGP (Edge Glued Panels). Glue line shear specimens were obtained from bonded joints glued with PVAc (Polyvinyl Acetate) and EPI (Emulsion Polymer Isocyanate) adhesives, using pieces oriented with tangential, radial and intermediary faces, as well as the combination between them. The specimens were submitted to two pretreatments in order to simulate the use of joints in dry and wet environments. For shear tests, 12 treatments were obtained. The results indicated that the use of tangential x tangential and tangential x intermediary bonding faces and EPI adhesive presented better glue line shear strength for EGP in dry and wet pretreatments, respectively. The joints bonded in the radial x radial direction presented statistically inferior values when compared to the other treatments.

Resumo Esta pesquisa teve como objetivo avaliar a qualidade de painéis aglomerados produzidos com seis espécies de madeiras tropicais da Amazônia: Byrsonima crispa, Eschweilera coriacea, Eschweilera odora, Manilkara amazonica, Pouteria guianensis e Swartzia recurva. Foram produzidos painéis experimentais com densidade nominal de 0,75 g/cm3, utilizando a resina uréia-formaldeído na proporção de 8% de sólidos - base peso seco das partículas. Os painéis foram prensados com pressão específica de 4,0 MPa, temperatura de 160 ºC e tempo de prensagem de oito minutos. Os painéis foram avaliados com base nas seguintes propriedades: razão de compactação, absorção de água e inchamento em espessura 2 horas e 24 horas, módulos de elasticidade e de ruptura, tração perpendicular, resistência ao arrancamento de parafusos na superfície e topo. A baixa razão de compactação dos painéis produzidos comas espécies tropicais não afetou de forma significativa os resultados de suas propriedades físicas e mecânicas. Avaliações comparativas dos resultados obtidos com os requisitos da norma EN 312 (2003) e espécie referencial - Pinus taeda, demonstraram que as espécies Byrsonima crispa, Eschweilera coriacea, Eschweilera odora e Pouteria guianensis apresentam grande potencial para produção de painéis aglomerados.

Abstract This research aimed to evaluate the quality of particleboard produced with six Amazonian tropical woods: Byrsonima crispa, Eschweilera coriacea, Eschweilera odora, Manilkara amazonica, Pouteria guianensis and Swartzia recurva. Experimental panels were produced with nominal density of 0,75 g/cm³, using the urea-formaldehyde resin in a proportion of 8% solids based on dry weight of the particles. The panels were pressed with a specific pressure of 4,0 MPa, temperature of 160 °C and pressing time of eight minutes. The panels were evaluated based on the following properties: compression ratio, water absorption and thickness swelling for 2 hours and 24 hours, modulus of elasticity and modulus of rupture, tension perpendicular, screws pullout resistance on the surface and top. Low compression ratio of panels produced with tropical wood species did not affect significantly the results of their physical and mechanical properties. Comparative evaluation of the results obtained with the requirements of EN 312 (2003) and reference species - Pinus taeda, showed that Byrsonima crispa, Eschweilera coriacea, Eschweilera odora and Pouteria guianensis have great potential for the production of particleboard.

RESUMO A presente pesquisa foi desenvolvida com o objetivo de avaliar o efeito dos sistemas de desdobro aleatório e otimizado em toras de Araucaria angustifolia em diferentes classes diamétricas, para obtenção de madeira serrada numa serraria de pequeno porte. Para o efeito, foram selecionadas 60 toras, as quais foram cubadas e separadas em três classes diamétricas com 20 toras que, em seguida foram divididas em dois lotes de 10 toras, sendo o primeiro lote submetido ao desdobro aleatório e o segundo, ao desdobro otimizado. Os resultados indicaram que o desdobro otimizado foi mais satisfatório e a classificação diamétrica ocasionou aumento do rendimento em madeira serrada nos dois sistemas de desdobro. Os modelos ajustados para predição do rendimento, em função da conicidade das toras, foram significativos e satisfatórios principalmente no sistema de desdobro otimizado, o qual teve altos coeficientes de determinação ajustados em relação ao sistema de desdobro aleatório.

ABSTRACT This research was developed in order to assess the effect of aleatory breakdown and optimized breakdown systems of the logs of A. angustifolia, using different diametric classes to obtain lumber in a small sawmill. For this, 60 logs were selected, cubed and separated in three diameter classes, with 20 logs each, which were additionally divided in two lots of 10 logs, being the first lots subjected to aleatory breakdown, and the second for optimized breakdown. The results indicated that the optimized breakdown was satisfactory; in addition, the diametric classification caused an increase in yield lumber on both breakdown systems. The adjusted models for the yield prediction due to the taper of the logs were significant and satisfactory, especially in the optimized breakdown system that had high determination coefficients adjusted, regarding the aleatory breakdown system.

Este trabalho teve como objetivo avaliar dois modelos de desdobro (radial e tangencial) de madeira de Eucalyptus cloeziana e Eucalyptus saligna, numa serraria portátil, para se eleger o qual proporciona maior rendimento em madeira serrada. Para o estudo, foram selecionadas aleatoriamente 24 árvores com 27 anos de idade, sendo 12 árvores de cada espécie e divididas em duas classes diamétricas: 30-34,5 cm e 35-39,5 cm. As árvores foram derrubadas e traçadas em toras de 3,4 m de comprimento, sendo produzidas tábuas de 25 mm de espessura nominal. Os resultados obtidos demostraram que, para as duas classes diamétricas de espécies, o modelo de desdobro tangencial obteve melhor desempenho em relação ao desdobro radial, em termos de rendimento. Pode-se concluir-se que o Eucalyptus cloeziana obteve melhores rendimentos, com maior destaque para o modelo de desdobro tangecial em relação ao modelo radial. Estas espécies, nas condições estudadas, têm potencial para ser uma fonte alternativa e segura para produção de madeira serrada, substituindo algumas espécies nativas, ora sob pressão, em Moçambique.

The present study aimed to evaluate two sawing models (radial and tangential) for Eucalyptus saligna and Eucalyptus cloeziana in a portable sawmill in order to select which one provides the highest lumber yield. To this end, twenty-four trees with 27 years of age were randomly selected: twelve of each species divided into two diameter classes, 30-34.5 and 35-39.5 cm. The trees were felled and cut in logs of 3.4 meters, and clapboards of 25 mm in nominal thickness were produced. The results obtained showed that, for both diameter classes in both species, the tangential sawing model provided higher yield compared with the radial sawing model. We conclude that lumber of satisfactory quality can be produced under the conditions studied and that these species present good potential to be used as an alternative and safe source of lumber production, being able to substitute some native species from Mozambique.