VARIAÇÃO INTRAESPECÍFICA NA ANATOMIA DO LENHO DE Hevea brasiliensis (Willd. ex A. Juss.) Mull. Arg. RELACIONADA À EXTRAÇÃO DE LÁTEX

Neste trabalho, foi estudada a influência da exploração do látex na anatomia do lenho de seringueiras nativas. Avaliou-se a hipótese de que as características anatômicas são afetadas pela atividade de extração do látex. Para isso, foram coletadas, de forma não-destrutiva, amostras em árvores nativas exploradas e não exploradas. As coletas foram feitas na Reserva Experimental de Catuaba, localizada em Senador Guiomard (AC). A estrutura anatômica do lenho foi analisada, sendo avaliados: o comprimento das fibras (não-gelatinosas e gelatinosas); diâmetro total e diâmetro do lume de fibras não-gelatinosas; diâmetro e frequência dos elementos de vaso; largura, altura e frequência de raios; e a proporção de tecidos. Árvores exploradas e não-exploradas diferiram na estrutura anatômica em relação às características quantitativas. Apenas as variáveis comprimento de fibra gelatinosa, diâmetro do lume das fibras, frequência de raios e proporção de elementos de vaso e raios não apresentaram diferenças significativas pelo teste de Mann-Whitney. Os resultados mais contundentes consistiram em aumento da largura e altura de raios nas árvores extraídas, bem como maiores proporções de fibras gelatinosas nas árvores não-extraídas. As diferenças observadas entre os grupos avaliados podem ser atribuídas à demanda de carboidratos que a regeneração do fluxo de látex ocasiona nesses indivíduos. Recomendam-se maiores estudos acerca do consumo de carboidratos não-estruturais, relacionados diretamente às mudanças na estrutura do xilema de seringueira

EFFECT OF GENETIC MATERIAL AND FERTILIZATION ON ESTIMATING THE DRYING POTENTIAL OF Tectona grandis Linn F.

Drying is a fundamental step in the lumber production process. The definition of variables that affect the quality of the process, such as initial and final temperatures as well as drying potential, depends on the known technological knowledge of the wood, as well as on the experience of the drying process developed for a particular species. With this in mind, we developed an experiment using wood from four genetic materials (three clones and one seminal) of the species Tectona grandis cultivated with and without fertilization. This was done to estimate and evaluate the parameters used in the explanation of drying programs. The values of the initial and final temperatures, and those of the drying potentials, were estimated using the drastic drying methodology, which evaluates the drying rate and defect score (cracks and collapse). In addition to the drying parameters, the physical properties that affect the drying performance were also evaluated. The results show that origin and fertilization did not affect the initial and final temperatures. However, the potential drying parameters were significantly affected by the combination of treatments. Furthermore, the wood drying potential of certain genetic materials was positively affected by fertilization. Finally, the material from the fertilized areas had the lowest basic densities, the highest initial moisture content, and the highest drying rates

INFLUENCE OF VAPORIZATION AND IMPREGNATION OF SILVER NANOPARTICLES ON THE DRYING RATE OF Eucalyptus pellita F. MUELL.

The aim of this study was to evaluate the effect of vaporization and impregnation of silver nanoparticles on the Eucalyptus pellita wood properties. For that, samples of three radial regions of the wood from three trees were vaporized for 12 and 24 hours and later on, they were immersed in solution of silver nanoparticles with and without application of vacuum (750 mm.Hg). Anatomical, physical and chemical analyzes of the wood were carried out in order to evaluate the effect of the treatments. The drying rate of the wood was determined in moisture bands before and after the fiber saturation point. Generally, the treatments did not modify the anatomical characteristics, permeability, and wood density in the three radial regions; however, the vaporization for 24h reduced the total extractive content in the wood. These results contributed in obtaining gains in the drying rate before and after the fiber saturation point. The effect of impregnation of nanoparticles with vacuum preceded by two periods of vaporization resulted in higher drying rates and the time of 24h stood out, resulting in the best averages among all treatments. The impregnation of nanoparticles had positive effects on the drying 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

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

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