Abstract The aim of this study was to verify the potential of the colorimetric technique in the identification of some species marketed as “tauari” in the Brazilian Amazon. CIE L* a* b* parameters were applied to determine the colour of 35 wood samples from the main wood poles of the State of Para, Brazil, and the scientific collections of the Museu Paraense Emilio Goeldi (Walter A. Egler Collection) and Embrapa Amazônia Oriental. From each sample, data were obtained in the three wood surfaces: transversal, longitudinal tangential and longitudinal radial. The coordinate b*, which showed the yellow pigment, exerted greater weight in the color characterization of the 35 samples marketed as tauari, being more evident in the tangential and radial sections. In PCA, MGW wood samples showed considerably distinct color patterns in relation to PA and IAN samples, and the h and L* parameters provided better informations for distinguishing species from sample sources. The colorimetric technique can be used as an auxiliary tool in the identification of wood. However, the simultaneous use of colorimetry with the anatomical description of wood is suggested, given the complexity of the species-level separation in “tauari” group.

Abstract: Because of the need for identification of forest species, especially for detection of illegal wood trade, the objective of this study was to evaluate the potential of colorimetry for differentiation of Inga vera Willd., Muellera campestris (Mart. ex Benth.) M.J. Silva & A.M.G. Azevedo and Machaerium paraguariense Hassl., species of the Fabaceae family, native to the Araucaria Forest in the state of Santa Catarina, southern Brazil. Discs at breast height were collected from three trees of each species and the colorimetric parameters (L*, a*, b*, C* and h) and visible spectra were evaluated in different radial position of the trunk (near bark, intermediate and near pith) and three different anatomical sections (transversal, radial and tangential surfaces). Mean values of hue angle (h) among the colorimetric parameters resulted in the highest potential for species discrimination. With respect to radial trunk position and anatomical section, parameters a* (green-red) and h were not statistically different, independent of the wood samples evaluated. For other parameters (L*, b* and C*), each species presented distinct results. Principal component analysis with second derivative of visible spectra discriminated all species. Colorimetry associated with chemometrics allowed to distinguish I. vera, M. campestris and M. paraguariense.

Abstract: The wood is exposed to possible damages caused by weather, requiring the application of a finishing coat to provide extra protection. The aim of this work was to evaluate the influence of the addition of microfibrillated cellulose in waterborne varnish on the colorimetric parameters, wettability and finish characteristics of wood products. Color was evaluated with a CM-5 spectrophotometer; surface wettability was analyzed by contact angle measurement using a drop shape analysis goniometer; and abrasion, adhesion and impact tests were performed to evaluate the quality of the coating. The coating’s optical characteristics were not affected by the addition of microfibrillated cellulose. The changes in wood wettability were small, with no statistical difference between the wood treated with plain varnish and that with unbleached microfibrillated cellulose. In the analysis of the variation of the contact angle during the elapsed time, the coating containing unbleached microfibrillated cellulose presented the best results. The results of finish quality did not show numerical changes after the addition of the microfibrillated cellulose, but qualitatively the microfibrillated cellulose caused better anchoring of the coating to the specimens. Therefore, the use of microfibrillated cellulose as reinforcement in coatings has potential, but tests with different consistencies and tests of other properties are necessary.

Abstract: Thermal modification is a treatment that seeks to improve the properties of wood and reduce the heterogeneity in its color. The objective of this work was to evaluate the effect of thermal treatment on the anatomical, chemical, physical, mechanical, colorimetric, and thermal stability properties of teakwood. For this, teakwood samples were treated by an industrial autoclave at final cycle temperature of 160 ºC. The reduction of cell wall thickness, the formation of cross-fissures and the crystallization of the wax inside the pores were observed in the anatomical structure. Chemically, the extractives evaporated and the polysaccharides ruptured, of which hemicellulose was the most affected. The heat treatment promoted lower equilibrium moisture, reducing the hygroscopicity and improving the dimensional stability of the wood. Considering the mechanical properties, the rupture modulus and the longitudinal and tangential hardness decreased after the heat treatment. The color of the wood changed significantly, from pink to dark brown. The treated wood had higher thermal stability, with greater weight loss at higher temperatures than the untreated wood.

Resumo O objetivo deste estudo foi avaliar as características de cor em amostras de madeira de Acacia mangium de uma plantação homogênea no estado da Bahia, nordeste do Brasil, e também analisar a influência da secção anatômica e posição radial do tronco na resposta de cor para contribuir com informações para o melhor aproveitamento da madeira, como por exemplo, a otimização do rendimento das peças em serraria através da forma estética mais aceitável pelo consumidor final. Foram cortadas seis árvores com idade de 14 anos. A espécie foi identificada por análise anatômica no Laboratório de Anatomia da madeira da Universidade Federal do Paraná, comparando a amostra coletada com o material autenticado. Um disco da base de cada árvore foi dividido em seis amostras orientadas em cortes anatômicos (transversal, radial e tangencial), com dimensões de 20 × 20 × 30 mm, próximo a medula, região intermediária e região próxima a casca. Foram avaliadas um total de 36 amostras, 12 de cada posição. A avaliação colorimétrica foi realizada com um espectrofotômetro CM-5. Foram obtidos dados sobre a luminosidade, coordenadas cromáticas verde-vermelho e azul-amarelo e foram calculados valores de saturação e ângulo de tonalidade. A madeira de Acacia de floresta plantada é classificada como cor de azeitona. Os parâmetros de cor foram influenciados pela secção anatômica e posição radial no tronco, sendo observado valores de luminosidade de 44 para a seção transversal, 55 para a tangencial e 57 para a radial. As secções transversais tinham valores mais baixos em comparação com as superfícies longitudinais e as secções radiais tinham maior luminosidade do que as secções tangenciais. A região próxima da casca apresentava valores mais baixos na maioria dos parâmetros colorimétricos, exceto o ângulo de tonalidade, em comparação com as regiões intermédias e próximas da medula, o qual está em torno de 70 para todas as posições na madeira.

Abstract The aim of this study was to evaluate color characteristics in wood samples from Acacia mangium from a homogeneous plantation in Bahia state, northeast Brazil, and also analyze the influence of anatomical section and radial position in the trunk on color response to contribute to information for the best use of the wood, such as, for example, the optimization of the performance of the pieces in sawmill through the most acceptable aesthetic form by the final consumer. Six trees with age of 14 years were cut. The species was identified by anatomical analysis at the Laboratory of Wood Anatomy of the Federal University of Paraná, comparing the sample collected with the authenticated material. A disc from the base of each tree was divided into six samples oriented in anatomical sections (transversal, radial and tangential), with dimensions of 20 × 20 × 30mm, named near pith, intermediate and near bark. A total of 36 samples were evaluated, 12 from each position. The colorimetric evaluation was performed with a CM-5 spectrophotometer. Data on lightness, green-red and blue-yellow chromatic coordinates were obtained, and values of saturation and hue angle were calculated. Acacia wood from planted forest is classified as olive color. Color parameters were influenced by anatomical section and radial position in the trunk, being found 44 for the transversal section, 55 for the tangential section and 57 in the radial for luminosity. Transversal sections had lower values in comparison to longitudinal surfaces and radial sections had higher luminosity than tangential sections. The near bark region presented lower values in most colorimetric parameters, except hue angle, in comparison with the intermediate and near pith regions, which was around 70 in the different positions of the wood.

SUMMARY: The aim of this study was to measure and compare some anatomical elements of wood and charcoal of Inga vera, Machaerium paraguariense and Muellera campestris to support identification of the materials seized by regulatory authorities. For each species, three trees were analyzed. After wood evaluation, all samples (moisture content of 12 ± 1 %) were wrapped in aluminum foil and carbonized in a muffle furnace for 8 hours with final temperature of 450 °C and a heating rate of 1.66 °C/min. The number of measurements was based on 30 readings regarding tangential diameter and vessel density, along with frequency, height and width of rays (in micrometers). After carbonization, changes in cell dimensions and different behavior were observed in the Fabaceae species evaluated. In all species, vessel diameter declined; vessel density decreased in Inga vera and increased in the other species; ray height decreased in Inga vera and Muellera campestris, and increased in Machaerium paraguariense; and ray width and frequency increased in all species. We concluded that due to the conservation of wood anatomical structures after carbonization, the inclusion of this species in a database would be effective to support efforts to control deforestation in the south of Brazil.

RESUMEN: El objetivo de este estudio fue medir y comparar algunos elementos anatómicos de madera y carbón vegetal de Inga vera, Machaerium paraguariense y Muellera campestris con el fin de apoyar la identificación de los materiales incautados por las autoridades reguladoras. Para cada especie, se analizaron tres árboles. Después de la evaluación de la madera, todas las muestras (contenido de humedad de 12 ± 1 %) se envolvieron en papel de aluminio y se carbonizaron en un horno de mufla durante 8 horas con una temperatura final de 450 °C y una velocidad de calentamiento de 1,66 °C/min. El número de mediciones se basó en 30 lecturas con respecto al diámetro tangencial y densidad de los vasos, junto con frecuencia, altura y ancho de los radios (en micrómetros). Después de la carbonización, se observaron cambios en las dimensiones celulares y diferentes comportamientos en las especies de Fabaceae evaluadas. En todas las especies, el diámetro del vaso disminuyó; la frecuencia de los vasos disminuyó en Inga vera y aumentó en otras especies; la altura de los radios disminuyó en Inga vera y Muellera campestris, y aumentó en Machaerium paraguariense; y el ancho y la frecuencia de los radios aumentaron en todas las especies. Concluimos que debido a la conservación de las estructuras anatómicas de la madera después de la carbonización, la inclusión de esta especie en una base de datos sería efectiva para apoyar los esfuerzos para controlar la deforestación en el sur de Brasil.

ABSTRACT In this study, based on the mechanical shear treatment, the cellulosic pulp was fibrillated in nanofibrils dispersed in aqueous suspension. Nanofibrillated Cellulose (NFC) matrix - Polyvinyl Alcohol (PVA) nanocomposite films’ were prepared by casting from NFC/PVA suspension mixtures. The thermal and mechanical properties of the obtained films were evaluated. Low levels (2, 5 and 10 wt%) of PVA were used as an additive in a nanofibrillated cellulose (NFC) matrix. The predominant use of NFC, with superior properties due to its purity, with an efficient and environmentally friendly method, has allowed the production of NFC-based biodegradable materials with enhanced properties for high-level applications. The addition of PVA to the NFC matrix produced positive results, as it causes little aesthetic interference, without changes in surface brightness. After the addition of PVA the films showed a great gain in mechanical strength, increasing by 24% in Young’s modulus with the addition of 10% PVA. Even after addition, the samples’ chemical composition remains unchanged and the mixture shows a decrease in the film surface hydrophilicity when compared to pure NFC. Composite material thermal analysis indicates that thermal degradation temperatures remain unchanged after the addition of PVA. Although PVA is not very temperature resistant, in the proportions used, NFC thermal resistance is preserved.

Resumo Com a determinação do quanto de biomassa florestal é gerada após as intervenções culturais é possível definir as áreas passíveis de exploração. Com isso, o objetivo do trabalho foi quantificar e estimar a oferta de biomassa de Pinus taeda L. disponível após as intervenções culturais. O experimento foi realizado em reflorestamentos nos municípios dos estados do Paraná e Santa Catarina, com idades de 3 anos (primeira desrama), 5 anos (segunda desrama), 7 anos (terceira desrama), 11 anos (primeiro desbaste) 19 anos (segundo desbaste), 23 e 33 anos (cortes rasos). Para cada idade foram amostradas 10 árvores e quantificados os componentes acículas, galhos, ponteira e casca. Após o corte raso, aos 23 anos houve maior disponibilidade de biomassa individual (372,6 kg.árv-1) e por unidade de área (144,4 t.ha-1), sendo composto principalmente por galhos (69,3%), seguido das acículas (17,9%), casca (11,0%) e ponteira (1,8%) por unidade de área. A correlação entre a massa dos componentes da biomassa por árvore e as variáveis independentes foi significativa e superior a 0,52. A menor correlação foi observada entre estas e a quantidade ofertada de ponteiras. Os modelos de regressão selecionados para estimar a massa de biomassa em função das variáveis independentes tiveram R2aju superiores a 83%, baixos desvios padrões e coeficientes de variação.

Abstract Along with the determination of how much of forest biomass is generated after the cultural interventions, it is possible to define areas that can be exploited. Thus, the objective of this work was to quantify and estimate the biomass supply of Pinus taeda L. available after cultural interventions. The experiment was carried out in populations in the cities of Paraná and Santa Catarina states, with ages of 3 years (first pruning), 5 years (second pruning), 7 years (third pruning), 11 years (first thinning), 19 years (second thinning), 23 and 33 years (harvesting). For each age, 10 trees were sampled and the components of the leaves, twigs, canopy and bark were quantified. After harvesting at 23 years old there was greater availability of individual biomass (372.6 kg. tree-1) and per unit area (144.4 t.ha-1), being composed mainly of twigs (69.3%), followed by leaves (17.9%), bark (11.0%) and canopy (1.8%) per unit area. The correlation between the mass of the components of the biomass per tree and the independent variables was significant and higher to 0.52. The lower correlation was observed between these and the mass of canopy. The regression models selected to estimate the mass of biomass from the independent variables had R2adju higher than 83%, low standard deviations and low coefficients of variation.

ABSTRACT Wood color and properties are variables among and within species, and fast and non-destructive techniques can be applied to their characterization, being also important in wood marketing and quality control. This paper evaluated the influence of age on the discrimination of Tectona grandis L.F. (teak) wood by VIS/NIR spectroscopy. Wood from three ages, with heartwood and sapwood, were studied, totaling 36 samples per age. Quantitative colorimetric data, based on CIELAB 1976, visible and NIR infrared spectra were collected from radial and tangential surfaces in five positions of each sample, in a total of 540 spectra. Both techniques were adequate for age discrimination in teak wood. Statistical differences were observed in the chromatic coordinates in heartwood and sapwood for each age. VIS/NIR spectroscopy can be applied for age discrimination based on teak solid samples and for wood quality control.

RESUMO Este trabalho investiga as propriedades físicas e mecânicas de filmes nanoestruturados produzidos a partir da polpa kraft branqueada de Pinus sp. Para obter a nanocelulose, a polpa kraft branqueada foi submetida a seis diferentes intensidades de desfibrilação pelo moinho: dois, cinco, dez, 20, 30 e 40 passes. A influência do número de passes foi avaliada por meio das propriedades físicas e mecânicas dos filmes. Os resultados indicam que a presença de nanofibrilas reduziu a espessura e aumentou consideravelmente os valores de densidade dos filmes fabricados. Observou-se aumento da resistência à tração de 300% e o índice de ruptura foi dez vezes maior em relação aos papéis normais. A estrutura mais compacta e a menor porosidade causada pela maior superfície de contato entre as nanofibrilas nos filmes resultaram em maiores valores de densidade, resistência à tração e resistência à ruptura.

ABSTRACT This study investigates the physical and mechanical properties of nanostructured films produced from Pinus sp. kraft pulp. To obtain the nanocellulose, the bleached kraft pulp was submitted to six different grinding regimes: two, five, ten, 20, 30, and 40 passes through the grinder. The influence of the number of passes was evaluated through the films’ physical and mechanical properties. The results show that the nanofibers reduced the thickness and considerably increased the density values of the fabricated films. The tensile strength increased more than 300% and the burst index was ten times higher in relation to normal papers. The more compact structure and lower porosity caused by the larger contact surface between nanofibers in the nanostructured films resulted in higher values of density, tensile strength, and burst resistance.

Abstract: The modification of wood by thermal treatments produces characteristic changes in its chemical composition and surface color and can improve the structural and esthetic quality. The objective of this paper is to evaluate the potential of near infrared and visible spectroscopy to predict the modifications in chemical composition of Eucalyptys grandis and Pinus taeda after thermal treatment. Near infrared and visible spectra were collected directly on the longitudinal surface of wood samples. The thermally modified wood of both species showed higher content of lignin and extractives than the untreated wood. There was darkening of thermally modified wood, as a result of chemical modification caused by heat. The Near infrared/visible technique identified the groups that were modified by treatment. NIR and visible spectroscopy can be used to predict chemical composition of natural or thermally treated Eucalyptus grandis and Pinus taeda.

Abstract: This study is a continuation of a previous study published in this journal, with the aim of evaluating the effect of the Brazilian industrial thermal modification process on some physical properties of Eucalyptus grandis juvenile wood. Flatsawn boards of juvenile wood were tested for four treatment levels: untreated and thermally modified wood at final cycle temperatures of 140 °C, 160 °C and 180 °C. Physical properties were assessed according to a standard of the Comisión Panamericana de Normas Técnicas and a method proposed by the specialized literature encompassing equilibrium moisture content (a measure of wood’s hygroscopicity), density (oven-dried and air-dried) and radial, tangential and volumetric swelling (from oven-dried to green moisture content). Thermally modified Eucalyptus grandis wood became less hygroscopic, more dimensionally stable (tangential and volumetric swelling) and less dense, even at the lowest temperature tested (140 °C), except for radial swelling, which did not differ from untreated wood.

Abstract: Correct identification of species in wood and charcoal commerce is important, and rapid and nondestructive evaluation based on near-infrared techniques can be a good alternative. Four trees from Combretum leprosum, Croton argyrophylloides, Jatropha mutabilis, Luetzelburgia auriculata, Mimosa tenuiflora and Poincianella bracteosa, were cut in a natural forest in the municipality of Coremas, Paraíba state and stem discs with thickness of about 80 mm were taken at 0, 25, 50, 75 and 100% of commercial height. For charcoal production, each sample was wrapped in aluminum foil and carbonized in a muffle furnace, with a final temperature of 450 °C and a heating rate of 1,66 °C min-1. Spectra were collected directly from sample surface. The best pretreatment was second derivative, while the best classification method was PCA-LDA, and the analysis of full spectra (4000-10000 cm-1) was indicated. In classification, there was no difference between surfaces where spectra was collected, so in practice, in commercial control for example, the information can be obtained from any surface. For rapid analysis for purposes of control of forest practices or illegal commerce, spectra collected directly from wood and charcoal can be applied to distinguish these six Caatinga species.

RESUMO O objetivo deste trabalho foi caracterizar celuloses microfibriladas (CMF) produzidas pelo processo mecânico, através de 10 passesno moinho Super Masscolloider Masuko Sangyo, utilizando polpa kraft industrial branqueada e não branqueada de Eucalyptus spp. A caracterização das CMF foi realizada através da morfologia (MET), cristalinidade, viscosidade, potencial zeta e análise termogravimétrica (TGA). Independentemente do tipo de fibra, o microprocessamento reduziu drasticamente as dimensões do material de modo a ser obtidas estruturas com dimensões de escala nanométrica. A CMF produzida com polpa não branqueada preservou a cor marrom original da polpa, o que pode ser vantajosa para algumas aplicações no setor de embalagem, enquanto que filmes produzidos com polpa branqueada são mais translúcidos. As CMF apresentaram menores valores de viscosidade e índice de cristalinidade em relação a polpa celulósica. O potencial zeta foi influenciado pelo tipo de fibra utilizado para produzir as CMF. As principais transições térmicas nas CMF ocorrem após 200 ºC, demonstrando o potencial desse material em aplicações com temperatura elevada.

ABSTRACT The aim of this study was to characterize microfibrillated cellulose (MFC) produced with a Masuko Sangyo Super Masscolloider using bleached and unbleached pulp of Eucalyptus spp. The MFC was characterized regarding morphology (TEM), crystallinity, viscosity, zeta potential and thermal properties (TGA). Regardless of the fiber type, the processing dramatically reduced the dimensions of the material, so as to obtain structures with nanometric dimensions. MFC produced with unbleached pulp preserved the original brown color of the pulp, which may be advantageous for some applications in the packaging sector, while films produced with bleached pulp were more translucent. The MFC showed lower values of viscosity and crystallinity index in relation to cellulosic pulp. The zeta potential was influenced by the type of fiber used. The main thermal transitions in MFC occurred after 200 ºC, demonstrating the potential of this material forhigh-temperature applications.

SUMMARY: Wood trade is strongly dependent on global economic conditions. In Africa, the market for tropical wood also has dynamic changes. In Mozambique, the international demand for wood comes mainly from emerging economies such as China and India. Almost 70 % of the country is still covered by forests and other woody vegetation. There are many species with favorable properties for wood commerce, although, at present, this is restricted to a few species. We analyzed the wood anatomy of Acacia nigrescens, Combretum imberbe, Icuria dunensis, Pericopsis angolensis and Sterculia appendiculata and comment about properties and potential use based on their anatomical composition. In general, the species presented wood diffuse pores, simple perforation plates, alternate intervessel pits, deposits in vessels; abundant axial parenchyma; multiseriate rays, very thick-walled fibers and mineral inclusions. Based on anatomical characteristics, the studied species have great potential for use in panels industry, furniture, floor, structures and craftwork.

RESUMEN: El comercio de madera depende en gran medida de las condiciones económicas globales. En África, el mercado de las maderas tropicales también tiene cambios dinámicos. En Mozambique, la demanda internacional de madera proviene principalmente de las economías emergentes como China e India. Casi el 70 % del país está todavía cubierta por bosques y otra vegetación leñosa. Hay muchas especies con propiedades favorables para el comercio de madera, pero en la actualidad esto está restringido a unas pocas especies. Se analizó la anatomía de la madera de Acacia nigrescens, Combretum imberbe, Icuria dunensis, Pericopsis angolensis y Sterculia appendiculata y se comenta las propiedades y el uso potencial en función de su composición anatómica. En general, las especies tienen porosidad difusa, placas de perforación simple, punteaduras intervasculares alternas, depósitos en los vasos; parénquima axial abundante; rayos multiseriados, fibras de paredes muy gruesas e inclusiones minerales. Según las características anatómicas, las especies estudiadas tienen un gran potencial para uso en la industria de paneles, muebles, pisos, estructuras y artesanía.