Márcio Pereira da Rocha

Avaliação das Principais Propriedades Físicas e Mecânicas da Madeira de Eucalyptus benthamii Maiden et Cambage

The present study aimed to assess the physical and mechanical properties of Eucalyptus benthamii Maiden et Cambage wood. The following physical properties were determined: apparent density at 12 and 0% moisture content, basic density, and indices of contraction. Mechanical properties were determined through tests of static bending, compression parallel to the grain, shear, and hardness in six-year-old wood. Based on the results obtained in the determination of physical properties, E. benthamii wood at the age studied can be classified as moderately heavy and dimensionally unstable. The species showed low resistance with respect to mechanical properties, which can be related to the large amount of juvenile wood observed in the material studied.

QUALIDADE DA SECAGEM CONVENCIONAL CONJUNTA DA MADEIRA DE CLONES DE TRÊS ESPÉCIES DE Eucalyptus sp.

The domestic industry commonly dries different species of eucalyptus in a same load because of the difficulty of identifying the species, hybrids and clones, and by optimizing the use of the kiln, too. However, this practice is not recommended in the literature. The objective of this study was to verify the quality of grouped conventional drying of Eucalyptus saligna , Eucalyptus grandis and Eucalyptus dunnii from clonal plantations. To this end, three loads were dried with the three species together in a pilot conventional dry kiln. The parameters used to analyze the quality of dried wood were final moisture content, end checks, surface checks, cupping, collapse, moisture gradient and drying stresses. Eucalyptus grandis showed the best quality of drying, followed by Eucalyptus saligna , and both species have potential to be kiln dried together. Eucalyptus dunnii had the worst quality of drying, and should not be kiln dried together with Eucalyptus grandis and Eucalyptus saligna . The basic density and shrink age were good parameters for the expected quality of the drying of eucalyptus species, in which less dense and more dimensionally stable species had better quality of drying. The drying schedule used must be modified to further drying of these species, especially regarding to uniformity and conditioning periods, which were considered insufficient.

Avaliação das Principais Propriedades Físicas e Mecânicas da Madeira de Eucalyptus benthamii Maiden et Cambage / Evaluation of the Main Physical and Mechanical Properties of Eucalyptus benthamii Maiden et Cambage Wood

The present study aimed to assess the physical and mechanical properties of Eucalyptus benthamii Maiden et Cambage wood. The following physical properties were determined: apparent density at 12 and 0% moisture content, basic density, and indices of contraction. Mechanical properties were determined through tests of static bending, compression parallel to the grain, shear, and hardness in six-year-old wood. Based on the results obtained in the determination of physical properties, E. benthamii wood at the age studied can be classified as moderately heavy and dimensionally unstable. The species showed low resistance with respect to mechanical properties, which can be related to the large amount of juvenile wood observed in the material studied.

COMPARISON BETWEEN WOOD DRYING DEFECT SCORES: SPECIMEN TESTING X ANALYSIS OF KILN-DRIED BOARDS

It is important to develop drying technologies for Eucalyptus grandis lumber, which is one of the most planted species of this genus in Brazil and plays an important role as raw material for the wood industry. The general aim of this work was to assess the conventional kiln drying of juvenile wood of three clones of Eucalyptus grandis. The specific aims were to compare the behavior between: i) drying defects indicated by tests with wood specimens and conventional kiln-dried boards; and ii) physical properties and the drying quality. Five 11-year-old trees of each clone were felled, and only flatsawn boards of the first log were used. Basic density and total shrinkage were determined, and the drying test with wood specimens at 100 °C was carried out. Kiln drying of boards was performed, and initial and final moisture content, moisture gradient in thickness, drying stresses and drying defects were assessed. The defect scoring method was used to verify the behavior between the defects detected by specimen testing and the defects detected in kiln-dried boards. As main results, the drying schedule was too severe for the wood, resulting in a high level of boards with defects. The behavior between the defects in the drying test with specimens and the defects of kiln-dried boards was different, there was no correspondence, according to the defect scoring method.

Avaliação do rendimento em madeira serrada de eucalipto para dois modelos de desdobro numa serraria portátil

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.

Avaliação do Rendimento em Madeira Serrada de Eucalipto para Dois Modelos de Desdobro numa Serraria Portátil / Evaluation of Yield in Lumber of Eucalyptus for Two Sawing Models in a Portable Sawmill

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.

Technological Feasibility of Hovenia dulcis thunb. Species for the Production of Edge Glued Panels

This study aims to evaluate the use of Hovenia dulcis wood to produce Edge Glued Panels – EGP. To this end, joints with dimensions of 5.0 × 31.0 × 2.5 cm (Width × Length × Thickness) were put together using polyvinyl acetate (PVAc) and emulsion polymer isocyanate (EPI) adhesives at a spread rate of 200 g.m-2 and the chemical characterization of the wood was performed. The strength of glued joints was evaluated through shear tests based on the procedures described by established standards. The results showed that the EPI adhesive achieved the best results in edge gluing to produce EGP. The use of PVAc adhesive did not show satisfactory results for edge gluing under these conditions. Hovenia dulcis wood is indicated for producing higher value-added wood products (VAWP) for external use purposes.

Insect damage in historic buildings of Colônia Murici - Southern Brazil

The historical buildings of Araucaria - Araucaria angustifolia (Bertol.) O. Kuntze 1898 (Araucariaceae) - present in the Murici Colony, municipality of SA£o JosA© dos Pinhais, ParanAi, Brazil, illustrate the development of constructive technique and native species processing. Such knowledge, brought by European immigrants in the late nineteenth century, provided the formation of a rich collection of wooden architecture in the state. However, this patrimony is deteriorated by the action of biological agents, especially xylophagous insects. In view of this, an entomological analysis was proposed through collections made in three buildings. Specimens of Coleoptera (Curculionidae and Ptinidae), Isoptera and Lepidoptera (Tineidae) were identified. It was concluded that Coleoptera (Ptinidae) and Isoptera represent the greatest risk to the installed wood. This emphasizes the importance of the entomological evaluation as a non-destructive method of diagnostic, that contributes to the verification of the health and safety of the structures.

Relação entre a deformação residual longitudinal com crescimento e propriedades da madeira de espécies de Eucalyptus

This study aimed to assess the relationship of longitudinal residual strain due to growth stresses with tree growth variables and the physical and mechanical properties of wood. The species studied were E. dunnii and E. grandis, both with 40, 52 and 64 months of age and E. saligna with ages 28, 40, 52 months of age for solid wood production. The growth stress levels were measured indirectly through the CIRAD-Forêt method. The physical and mechanical properties of wood were obtained in accordance with the standards of COPANT (1972a). Correlations among longitudinal residual strain with tree growth variables and physical and mechanical properties showed a high dispersion; wood at 52 months of age exhibited a more obvious correlation among investigated variables. Thus, forest breeding programs, associated with increments of new silvicultural practices should be directed to the production of wood with desirable characteristics for obtaining the solid wood with low propensity for growth stress.

Ensaio de Taxa de Secagem e Escore de Defeitos para a Predição da Qualidade da Secagem Convencional da Madeira de Eucalyptus sp. – Parte 2

This research is a continuation of Klitzke & Batista (2010) work. The main objective was to assess whether the wood quality in the methodology of drastic drying test at 100 °C corresponds to that of conventional kiln drying. It was used 11 years old Eucalyptus saligna, Eucalyptus grandis and Eucalyptus dunnii woods, which were kiln dried together in the same batch in a pilot scale kiln, doing three repetitions. Drying defects evaluated were end and surface cracks, cupping and collapse, which generated a mean score by species, which was compared to the score of defects of the drastic drying test, as well as to the basic density and the total volumetric shrinkage. Eucalyptus grandis and Eucalyptus saligna had higher wood quality in conventional drying than Eucalyptus dunnii. It was rejected the hypothesis of using the score of defects in drastic drying test as a way of predicting the quality of conventional kiln drying.