LUMBER YELD IN FUNCTION OF DIAMETER CLASSES AND QUALITY STANDARDS OF LOGS

AbstractThe objective of this study was to determine and evaluate the yield of four (4) diameter classes in function of quality of logs, in logwood processing of Cedrinho (Erisma uncinatumWarm.). 20 logs of four diameter classes between 46 and 85 cm were selected and classified in terms of quality, being 5 logs for each diameter class. Diameter class I resulted in the lowest yield and diameter class III showed the highest yield. Yield increased according to the diameter of the logs in classes I, II and III. Class IV logs with larger diameters had quality defects such as cracks and internal flaws, causing a small yield drop. It could be concluded that there was a correlation between diameter and yield.Keywords: Mato Grosso; sawmill; native wood; correlation. ResumoRendimento de madeira serrada em função de classes diamétricas e padrões de qualidade da tora. O objetivo deste trabalho foi determinar e avaliar o rendimento em diferentes classes diamétricas em função da qualidade das toras no desdobro do Cedrinho (Erisma uncinatum Warm.). Foram selecionadas e classificadas quanto à qualidade 20 toras em quatro classes diamétricas, entre 46 e 85 cm, sendo cinco toras para cada classe diamétrica. A classe diamétrica I apresentou o menor rendimento e a classe diamétricaIII apresentou o maior. O rendimento aumentou de acordo com o diâmetro das toras na classe I, II e III. As toras da classe IV, com maiores diâmetros, apresentaram baixa qualidade, com defeitos como rachaduras e falhas internas, causando uma pequena queda no rendimento. Pode-se dizer que existe uma correlação entre diâmetro e rendimento. Palavras-chave: Mato Grosso; serraria; madeira nativa; correlação.AbstractThe objective of this study was to determine and evaluate the yield of four (4) diameter classes in function of quality of logs, in logwood processing of Cedrinho (Erisma uncinatumWarm.). 20 logs of four diameter classes between 46 and 85 cm were selected and classified in terms of quality, being 5 logs for each diameter class. Diameter class I resulted in the lowest yield and diameter class III showed the highest yield. Yield increased according to the diameter of the logs in classes I, II and III. Class IV logs with larger diameters had quality defects such as cracks and internal flaws, causing a small yield drop. It could be concluded that there was a correlation between diameter and yield.Keywords: Mato Grosso; sawmill; native wood; correlation

Influence of geometry of the band-saw blades teeth in lumber quality and productivity

ResumoEste trabalho teve como objetivo avaliar o comportamento de dois modelos de dentes de lâmina de serra fita, durante o processamento mecânico de toras de Erisma uncinatum (cedrinho) e Dipteryx odorata (cumaru). A pesquisa levou em consideração aspectos qualitativos e quantitativos avaliados durante o desdobro de toras das duas espécies utilizando-se dois modelos de dentes de serra, modelo tradicional e modelo Senai. As variáveis que definiram a qualidade e a produtividade da madeira serrada, para ambos os modelos de dentes, foram, respectivamente, o desvio de corte e a velocidade de avanço do carro porta-tora. Os resultados mostraram que, para o modelo de dente denominado SENAI (MS), ganhos consideráveis em produtividade foram obtidos apenas para a espécie Erisma uncinatum. Essa vantagem não foi observada quando as toras processadas foram da espécie Dipteryx odorata, devido à consequente redução da velocidade de avanço. Em termos qualitativos, os ganhos obtidos com o modelo proposto foram observados para as duas espécies de madeira processada, com maior ênfase para madeira de cedrinho. Considerando esses resultados, o modelo Senai (MS) foi o mais recomendado para as condições de desdobro empregado, uma vez ter demonstrado ser o mais efetivo em termos de rendimento e, especialmente, qualidade de corte.Palavra-chave: Processamento mecânico de toras; ângulos de corte; velocidade de avanço. AbstractInfluence of geometry of the band-saw blades teeth in lumber quality and productivity. This research aimed to evaluate the behavior of two tooth models of band-saw blades, during log mechanical processing of Erisma uncinatum (cedrinho) and Dipteryx odorata (cumuru) using two types of sawtooth models: traditional model and Senai model. The research focused qualitative and quantitative aspects, evaluated during the sawing of the two species. The variables that define sawn wood quality and productivity, for both tooth models, were, respectively, the cut deviation, and the advancement velocity of log porter car. The results revealed that the “SENAI (MS)” tooth model has considerable productivity gains, only for de Erisma uncinatum specie. These advantages were not observed for the Dipteryx odorata species processed logs, due to consequent advancement velocity reduction. In qualitative terms, gains with the considered model could be observed for the two processed species, with emphasis for the medium density species. Considering the results, the Senai model (MS) was the most recommended for the applied sawing conditions, once the results demonstrated more qualitative effectiveness.Keywords: Mechanical processing of logs; cutting angles; feed rate.AbstractThis research aimed to evaluate the behavior of two tooth models of band-saw blades, during log mechanical processing of Erisma uncinatum (cedrinho) and Dipteryx odorata (cumuru) using two types of sawtooth models: traditional model and Senai model. The research focused qualitative and quantitative aspects, evaluated during the sawing of the two species. The variables that define sawn wood quality and productivity, for both tooth models, were, respectively, the cut deviation, and the advancement velocity of log porter car. The results revealed that the “SENAI (MS)” tooth model has considerable productivity gains, only for de Erisma uncinatum specie. These advantages were not observed for the Dipteryx odorata species processed logs, due to consequent advancement velocity reduction. In qualitative terms, gains with the considered model could be observed for the two processed species, with emphasis for the medium density species. Considering the results, the Senai model (MS) was the most recommended for the applied sawing conditions, once the results demonstrated more qualitative effectiveness.Keywords: Mechanical processing of logs; cutting angles; feed rate

DIAMETRIC GROWTH AND PROPERTIES OF Copaifera langsdorffii DESF. BY SECOND CUTTING CYCLE

The aim of this study was to analyze forest management effects in the diametric growth and wood anatomical, chemical and physical properties of Copaifera langsdorffii trees, in an Ombrophilous Open Forest (state of Mato Grosso, Brazil). The forest management effects were determined through a comparative study between the wood properties of 10 years before and 10 years after the first logging, in 1987. Multivariate associations among the anatomical characteristics, macro and micronutrient, wood density, and current annual increment (ICA) were evaluated to every growth period through the two steps cluster analysis. The results indicated that the following characteristics were relevant to distinct the periods studied: ICA, vessel frequency, and wood density. C. langsdorffii respond to stimuli caused by forest management, adapting to the increase of resources availability, due to the opening gaps, and showing growth increase with reduction of wood density, which may indicate variations on the wood properties.The aim of this study was to analyze forest management effects in the diametric growth and wood anatomical, chemical and physical properties of Copaifera langsdorffii trees, in an Ombrophilous Open Forest (Mato Grosso, Brazil). The forest management effects were determined through a comparative study between the wood properties of 10 years before and 10 years after the first logging, in 1987. Multivariate associations among the anatomical characteristics, macro and micronutrient, wood density, and current annual increment (ICA) were evaluated to every growth period through the two steps cluster analysis. The results indicated that the following characteristics were relevant to distinct the periods studied: ICA, vessel frequency, and wood density. C. langsdorffii respond to stimuli caused by forest management, adapting to the increase of resources availability, due to the opening gaps, and showing growth increase with reduction of wood density, which may indicate variations on the wood properties

Dendrochronology and growth of Copaifera langsdorffii wood in the vegetation dynamics of the Pirapitinga Ecological Station, state of Minas Gerais, Brazil

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

Produção de painéis de cimento-madeira com adição de diferentes proporções de casca e microssílica.

This work’s objective was to evaluate the effect of three percentages of addition of microsilica (0, 20 and 30%) on the physical and mechanical properties of wood-cement bonded particleboards of Eucalyptus urophylla composed by three wood:bark ratios (100:0, 95:5 and 90:10). Results showed that the most significant effect of the additive on the produced panels was in those containing bark, and that of 20% of additive was more efficient on the physical and mechanical properties.O objetivo deste trabalho foi avaliar o efeito da adição de microssílica em três porcentagens (0, 20 e 30%) sobre as propriedades físicas e mecânicas de painéis cimento-madeira de Eucalyptus urophylla compostos por três relações madeira:casca (100:0, 95:5 e 90:10). Os resultados mostraram que o efeito mais significativo do aditivo sobre os painéis produzidos ocorreu naqueles que continham casca, e que a adição de 20% do aditivo foi mais eficiente sobre as propriedades físicas e mecânicas

PRODUCTION OF WOOD-CEMENT BONDED PARTICLEBOARDS WITH DIFFERENT CONTENTS OF BARK AND MICROSILICA

O objetivo deste trabalho foi avaliar o efeito da adi\ue7\ue3o de micross\uedlica em tr\ueas porcentagens (0, 20 e 30%) sobre as propriedades f\uedsicas e mec\ue2nicas de pain\ue9is cimento-madeira de Eucalyptus urophylla compostos por tr\ueas rela\ue7\uf5es madeira:casca (100:0, 95:5 e 90:10). Os resultados mostraram que o efeito mais significativo do aditivo sobre os pain\ue9is produzidos ocorreu naqueles que continham casca, e que a adi\ue7\ue3o de 20% do aditivo foi mais eficiente sobre as propriedades f\uedsicas e mec\ue2nicas.This work\u2019s objective was to evaluate the effect of three percentages of addition of microsilica (0, 20 and 30%) on the physical and mechanical properties of wood-cement bonded particleboards of Eucalyptus urophylla composed by three wood:bark ratios (100:0, 95:5 and 90:10). Results showed that the most significant effect of the additive on the produced panels was in those containing bark, and that of 20% of additive was more efficient on the physical and mechanical properties

Variabilidad radial física y anatómica del leño de árboles de Amburana cearensis

Existen pocos estudios relacionados con microdensitometría de rayos X en madera de bosques tropicales nativos. Este estudio tuvo como objetivo determinar la variación radial de la densidad aparente del leño de Amburana cearensis (Allemão) A.C.Sm. por microdensitometría de rayos X. Se seleccionaron 11 árboles, de los que se cortaron secciones radiales de la médula a la corteza, para establecer la densidad aparente y las características anatómicas en tres posiciones radiales. Los resultados mostraron que la madera de A. cearensis presentó valores medios de densidad de madera, mínimo y máximo de 0.55, 0.13 y 0.87 g.cm-3,respectivamente. Asimismo, mostró diferencia significativa en tres posiciones médula (intermedia y corteza), esta diferencia puede ser explicada por la anatomía microscópica, especialmente con los vasos (diámetro, área y el número.mm-2). La microdensitometría de rayos X es una herramienta importante en la evaluación radial de la madera y puede ayudar en la definición de los límites de los anillos de crecimiento de A. cearensis

Variabilidad radial física y anatómica del leño de árboles de Amburana cearensis

There are few studies related with X-ray micro-densitometry regarding wood from native tropical forests. The objective of this study was to determine the radial variation of the apparent density of the Amburana cearensis wood by X-ray micro-densitometry. Indeed, eleven trees were selected, in which radial sections were cut from the pith to the cortex, in order to determine the apparent density and the anatomical characteristic in three radial positions. The results showed that the wood of A. cearensis presented mean values of wood density, minimum and maximum of 0.16 and 0.87 g.cm-3 respectively. Moreover, the wood showed significant difference in three positions of the pith, (intermediate and cortex), and this difference can be explained by the microscopic anatomy, especially with the vessels (diameter, area and number.mm-2). X-ray micro-densitometry is an important tool in the radial evaluation of wood and can help in the definition of the growth rings’ limits of A. cearensis.Existen pocos estudios relacionados con microdensitometría de rayos X en madera de bosques tropicales nativos. Este estudio tuvo como objetivo determinar la variación radial de la densidad aparente del leño de Amburana cearensis (Allemão) A.C.Sm. por microdensitometría de rayos X. Se seleccionaron 11 árboles, de los que se cortaron secciones radiales de la médula a la corteza, para establecer la densidad aparente y las características anatómicas en tres posiciones radiales. Los resultados mostraron que la madera de A. cearensis presentó valores medios de densidad de madera, mínimo y máximo de 0.55, 0.13 y 0.87 g.cm-3,respectivamente. Asimismo, mostró diferencia significativa en tres posiciones médula (intermedia y corteza), esta diferencia puede ser explicada por la anatomía microscópica, especialmente con los vasos (diámetro, área y el número.mm-2). La microdensitometría de rayos X es una herramienta importante en la evaluación radial de la madera y puede ayudar en la definición de los límites de los anillos de crecimiento de A. cearensis