Ricardo Jorge Klitzke

Densidade básica e retratibilidade da madeira de clones de três espécies de Eucalyptus

Among the planted forests that supply the national wood industry, the genus Eucalyptus has become the most important, due to its fast growth, ease of large scale planting and variability of wood use. The generation of new hybrids and clones is a reality in the national practice of silviculture, and there is great interest currently in finding genetic improvements, mainly for higher volumetric gains and resistance in rough conditions of planting, such as pest attacks, periods of drought, low soil fertility, etc. The basic density is one of the most important physical properties of wood because it relates directly to other properties, including the anisotropic shrinkage. Such properties indicate the rational use of a species in a certain wood product. The aim of this work was to determine the basic density and the anisotropic shrinkage of five wood clones for each one of the following species: Eucalyptus saligna, Eucalyptus grandis and Eucalyptus dunnii . Clone 5 of Eucalyptus saligna presented the highest basic density (0.56 g/cm³) and was the most dimensionally instable. Of all the species, there was only a direct relation among basic density, maximum volumetric shrinkage and maximum volumetric shrinkage coefficient in this clone. Considering maximum volumetric shrinkage as the criterion, clone 3 was the most dimensionally stable. Clones 2 and 3 of Eucalyptus grandis presented the least and the highest basic density, respectively, with 0.40 and 0.49 g/cm³. It was not possible to distinguish among clones 1, 3 and 4 in terms of dimensional stability, and considering maximum volumetric shrinkage coefficient as the criterion, clone 5 was the most dimensionally instable. For Eucalyptus saligna and Eucalyptus dunnii it was not possible to distinguish which clone presented the least basic density. Clone 3 of Eucalyptus dunnii presented the highest basic density (0.65 g/cm³) and considering maximum volumetric shrinkage coefficient as the criterion, it was the most dimensionally instable clone, whereas considering maximum volumetric shrinkage, clone 1 was the most stable. Eucalyptus grandis presented the least basic density and was the most stable, while Eucalyptus dunnii presented the highest basic density and was the most dimensionally instable.

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.

Efeito do tempo e da temperatura de modificação térmica na redução do inchamento máximo da madeira de Eucalyptus grandis Hill ex Maiden

Thermal rectification of wood was developed in the decade of 1940 and has been largely studied and produced in Europe. In Brazil, the research about this technique is still little and sparse, but it has gained attention nowadays. The aim of this study was to evaluate the influence of time and temperature of rectification on the reduction of maximum swelling of Eucalyptus grandis wood. According to the results obtained it is possible to achieve reductions of about 50% on the maximum volumetric swelling of Eucalyptus grandis wood. Best results were obtained for 230°C of thermal rectification rather than 200°C. The factor temperature was more significant than time, once that there was no significant difference between the times used (1, 2 and 3 hours). There was no significant interaction between the factors time and temperature.

Effect of Steaming on the Colorimetric Properties of Eucalyptus saligna Wood

This study aimed to homogenize the color of Eucalyptus saligna wood by means of steaming and compare the resulting color with that of Cariniana legalis wood, a species of high commercial value. To this end, two steaming curves were tested: 100% relative humidity for 12 (T1) and 24 (T2) hours at 90 °C followed by drying in a pilot-scale conventional kiln. The colorimetric parameters L*, a*, b*, C*, and h were determined according to the CIE L*a*b* color measurement system after drying. Results showed that steaming can be used for color homogenization between heartwood and sapwood. The treatment conducted for 24 hours (T2) presented the best results.

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.