RESUMOO objetivo deste estudo foi avaliar a qualidade da secagem da madeira de Eucalyptus pellita previamente submetidas aos processos de anelamento e vaporização. A metodologia baseou-se na hipótese de que o uso das técnicas conjuntas de anelamento e vaporização diminuiriam os defeitos apresentados pela madeira serrada após a secagem. Doze árvores de Eucalyptus pellita foram coletadas e seccionadas em toras de três metros de comprimento. A metade destas passou pelo processo de anelamento radial e a outra metade foi vaporizada a 82 ºC. Após o desdobro, as tábuas foram submetidas a secagem em estufa convencional utilizando um programa considerado severo para a madeira de eucalipto. O objetivo disso foi potencializar o aparecimento de defeitos e assim, analisar o efeito dos tratamentos na minimização dos mesmos. Pode-se concluir que a realização do anelamento e aplicação da vaporização melhorou a qualidade da madeira serrada sem comprometer o rendimento final. Os defeitos de encurvamento, arqueamento e encanoamento foram considerados leves, apesar da secagem severa.Palavras-chave: Defeitos de secagem, qualidade da madeira, secagem severa Log steaming and ringment for optimization of eucalyptus wood drying process ABSTRACTThe aim of this study was to evaluate the quality of lumber Eucalyptus pellita previously subjected to annealing processes, steaming and drying under severe drought. The methodology used was based on the hypothesis that the use of combined techniques girdling and spraying would reduce the defects in the lumber after drying. Twelve trees of Eucalyptus pellita were collected, sectioned into three logs 3.0 meters where half of the total spent by annealing (1/3 radius) and the other half were steamed until the center of the logs reached 82ºC. Then the logs were split into boards by successive cuts tangential using a horizontal band saw. The boards went to a conventional drying oven, where a drying program considered severe for eucalyptus wood applied. After drying, it was determined the main defects occurred on tablets, such as cracking index, boards crook, boards bow, cup boards and presence of collapse. Overall, it was concluded that the completion of ring and application of spray improved the quality of lumber Eucalyptus pellita without compromising the final yield of the material. Defects in curving, arching and curling were considered mild, despite the severe drying.
This study aims to build a chronology of the growth rings of Copaifera langsdorffii (copaíba) in order to understand the dynamics of vegetation types that occur on a river island in the Cerrado biome. For this purpose, we selected 30 trees of copaíba established in a vegetation of Mata Seca Sempre-Verde in the Pirapitinga Ecological Station (EEP), state of Minas Gerais, Brazil. Two radial samples from each tree were collected by an auger. The samples were treated by mechanical polishing for better visualization of the growth rings, and consequently further delineation and measurement. Later, the width of the growth rings was verified in order to generate a master time series of the specie. To check the influence of meteorological factors, we used the Pearson correlation (p < 0.05). The results showed that the population of copaíba in the EEP presented dendrochronologyc potential, which was confirmed by the high values of wide growth rings correlation within and between trees. The dendrochronologyc analysis revealed that copaíba trees were already present before the dam filling, but with lower population density than today. It was also possible to infer that the development of the vegetation type Mata Seca Sempre-Verde occurred since the decade of the 1970. The average sensitivity was enough to consider the species sensitive to environmental variations. Precipitation and temperature only influenced positively the growth rings in the transition from dry to wet seasons. The results revealed information about the dynamics of the local vegetation, elucidating the changes that occurred in the environment in which the population of copaíba is established.
The objective of this study was to characterize the wood anatomical structure of a rubber tree clone, under the influence of two different canopy grafts. The following rubber trees were selected in the system of a double-grafted PB 311 + FX 2784 and PB 311 + MDF 180. For each tree, discs of wood were cut from the affected branch immediately below the insertion of clone at right angles to the axis, from which the regions corresponding to tension, in opposite and normal wood, were identified. The anatomical analyses were conducted in accordance with the standards established by the International Association of Wood Anatomy Committee. The Kruskal-Wallis nonparametric test was applied for multiple comparisons among the types of woods and radial positions studied, at 5% of significance. Still, multivariate associations were assessed among the anatomical characteristics of both double-grafted rubber trees, by means of a two-step cluster analysis. Quantitative morphological differences were observed in the wood cells of the double-grafted studied clones. The ray height and the vessels diameter were the most important morphologic characteristics for the distinction. The canopy clone exhibited the ability to modulate the quantitative anatomical characters of the panel clone, depending on the plant’s needs.
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