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http://dx.doi.org/10.5902/1980509819609Os objetivos deste estudo foram: avaliar a durabilidade natural de três espécies de tauari (Couratari guianensis Aublet, Couratari oblongifolia Ducke & Knuth R. e Couratari stellata A.C.Smith), relatar os parâmetros colorimétricos de acordo com o sistema CIE L * a * b * 1976 assim como mostrar a aparência dos blocos de madeira antes e após o ataque. Dois fungos de podridão-parda [Gloeophyllum trabeum (Persoon ex Fries) Murril. e Lentinus lepideus Fr.] e dois de podridão-branca [Trametes versicolor (Linnaeus ex Fries) Pilat e Ganoderma applanatum (Pers. ex Wallr.)] foram utilizados. A madeira de tauari foi classificada como "moderadamente resistente" a "resistente" quando exposta aos fungos Gloeophyllum trabeum, Trametes versicolor e Ganoderma applanatum. O conteúdo de extrativos das amostras atacadas diminuiu quando comparado com o controle, exceto Couratari stellata expostos a Ganoderma applanatum. Por outro lado, os conteúdos de cinzas aumentaram quando comparados com o controle, exceto para a madeira de Couratari stellata exposto ao Gloeophyllum trabeum. Todos os blocos de madeira atacados e as serragens tornaram-se mais escuras, exceto para a serragem de Couratari stellata exposto ao fungo Trametes versicolor, e mais vermelho do que a amostra sem ataque. O ΔE * médio do bloco de madeira e serragem, atacados, atingiram 29,5 e 14,3, respectivamente.

Woods of 36 tree species from the Brazilian Amazon forest have been extracted and analyzed by means of total hydrolysis. For each species, three trees were analyzed in duplicate. The sugars and other byproducts of hydrolysis were analyzed by HPLC. Uronic anhydrides and acid-soluble lignin were determined by colorimetric methods. Acid-insoluble lignin, ash, and extractive contents were analyzed gravimetrically. Each analysis was performed several times and the data were evaluated statistically. The average percentages for ash and extractives are presented. Quantitative data for sugars obtained by HPLC were recalculated for glucan, galactan, arabinan, and mannan contents. These data are presented together with quantitative data for acetyl groups, 5-hydroxymethyl-2-furfuraldehyde, levulinic acid, uronic anhydride, acid-soluble and -insoluble lignin as summative analysis data based on an ash- and extractive-free basis, where, in an ideal case, the data should sum up to 100%. The summative results obtained varied from 96.0% to 99.6%, which is very satisfactory.

Chapas de partículas de cimento-madeira foram confeccionadas com a madeira de quatro clones de Hevea brasiliensis Müll. Arg. (seringueira): IAN 717, IAN 873, GT 711 e AVROS 1301. Confeccionaram-se as chapas na proporção de 1:4:1 (madeira:cimento:água) por peso e nas dimensões de 450 x 450 x 13 mm e densidade nominal de 1,4 g/cm³, com a adição de 4% de cloreto de cálcio di-hidratado (CaCl2.2H2O) como acelerador. Foram testadas partículas fervidas e não-fervidas dos quatro clones, totalizando oito tratamentos, sendo em cada um destes, com quatro repetições, avaliadas as propriedades mecânicas e físicas das chapas, segundo a norma ASTM D 1037 - 96a. De forma geral, os melhores resultados de propriedades físicas e mecânicas foram obtidos nas chapas com partículas do clone AVROS 1301. No teste de hidratação do cimento, a madeira de seringueira in natura foi classificada como de "inibição extrema", porém com a adição de CaCl2 o foi como de "baixa inibição". Essa madeira se mostrou tecnicamente viável à produção de chapas de cimento-madeira, independentemente do clone.

This research is part of a general study on the properties of oriented strandboard (OSB) using wood strands of species from Brazilian planted forests. The OSB industry is the latest wood related activity established in Brazil. In this particular part of the study, 80 mm long strands of Pinus taeda L. were bonded using two resin types (urea-formaldehyde and phenol-formaldehyde) at two levels of resin content (5% and 8%) to produce three-layer cross-aligned OSB to a face to core layer ratio of 1:2 and target density of 0.75 g/cm3. Physical and mechanical properties of the boards were evaluated according to ASTM standard D 1037-96a (1997) and the results compared to standards available as requirements for commercial structural panels. The results indicate that all the mechanical properties evaluated were above the requirements set forth by the Canadian standard CSA O437.0 (1993) for structural panels. The results of Janka hardness were in average 4 folds higher than the minimal requirements for Grade R-1 waferboard. Screw withdrawal values were also above the minimum required by grade M-3 of ANSI A208.1 standard (1993). Nevertheless, values of thickness swelling and water absorption were very high. The low dimensional stability may be related to the high density of the boards (“springback” effect) and also to the fact that no wax was used.

Conduziu-se este trabalho, com os objetivos de: avaliar a resistência natural de painéis reconstituídos e da madeira de Toona ciliata ao ataque de fungos por meio de ensaio acelerado de laboratório; caracterizar seus componentes anatômicos segundo IAWA; quantificar os valores de lignina solúvel e insolúvel; das amostras por hidrólise ácida e os parâmetros colorimétricos antes e após o ataque dos fungos, utilizando o sistema CIE-L*a*b*(1976). A madeira sólida foi classificada como moderadamente e altamente resistente ao fungo de podridão branca (Trametes versicolor) e parda (Gloeophyllum trabeum). Os painéis OSB foram resistentes e moderadamente resistentes à podridão branca e para a parda, foram altamente resistentes. A variação de espécies e partículas não teve efeito positivo nos tratamentos. Com relação à madeira, ambos os fungos apresentaram inibição, em razão da presença de resina fenólica. Os aglomerados foram classificados como moderadamente resistentes à podridão branca. Os tratamentos T2 (cedro) e T4 (cedro-eucalipto) foram resistentes, mas o T3 (cedro-pinus) não resistiu ao ataque do fungo de podridão parda. A resina uréia-formaldeído não inibiu os ataques como a fenólica. Anatomicamente, a espécie apresentou textura média, linhas vasculares retilíneas, cheiro agradável ao corte e superfície radial pouco lustrosa. Sua estrutura anatômica favoreceu a colonização das hifas dos fungos. Todos os tratamentos ocasionaram escurecimento, após o ataque do fungo G. trabeum, com variação total da cor. Observou-se que, com a perda de massa, houve aumento nos teores de lignina insolúvel, para todos os tratamentos, indicando que essa propriedade química é um fator determinante na resistência da madeira ao ataque dos fungos avaliados. The objectives of this study were to evaluate the natural resistance of composite and solid wood panels from Toona ciliata to fungal attack through accelerated laboratory testing, to characterize the anatomical components of the wood according to IAWA, to quantify the soluble and insoluble lignin contents by acid hydrolysis and to determine the colorimetric parameters before and after fungal attack by using the CIE-L*a*b*(1976) system. Solid wood was classified as moderately and highly resistant to white-rot fungus (Trametes versicolor) and to brown-rot fungus (Gloeophyllum trabeum). OSB panels were found to be resistant and moderately resistant to white-rot fungus and highly resistant to brown-rot fungus. Variation in species and particle type did not have a positive effect on the treatments. As regards the wood, both fungi were inhibited by the presence of phenolic resin. Particleboard panels were classified as moderately resistant to white-rot fungus. Treatments T2 (cedar) and T4 (cedar-eucalyptus) were resistant while treatment T3 (cedar-pine) was not resistant to attack by brown-rot fungus. The urea-formaldehyde resin failed to inhibit attack in the same way the phenolic resin did. Anatomically, the species was found to have medium texture, straight vessel lines, pleasant smell after incision and poor luster on the radial surface. Its anatomical structure favored colonization by the threadlike filaments of the fungi. All treatments caused wood darkening after attack by the G. trabeum fungus, with total variation in color. It was observed that with weight loss an increase followed in insoluble lignin contents, in all treatments, indicating that this chemical property is a determining factor in wood resistance to the attack of the fungi being evaluated.

Mahogany is one of the most valuable woods and was widely used until it was included in Appendix II of the Convention on International Trade in Endangered Species as endangered species. Mahogany wood sometimes is traded under different names. Also, some similar woods belonging to the Meliaceae family are traded as “mahogany” or as being of a “mahogany pattern”. To investigate the feasibility of the use of near infrared spectroscopy for wood discrimination, the mahogany (Swietenia macrophylla King.), andiroba or crabwood (Carapa guianensis Aubl.), cedar (Cedrela odorata L.), and curupixá (Micropholis melinoniana Pierre) woods were examined. Four discrimination models based on partial least squares-discriminant analysis were developed based on a calibration set composed of 88 samples and a test set with 44 samples. Each model corresponds to the discrimination of a wood species from the others. Optimization of the model was performed by means of the OPUS® software followed by statistical analysis software (Matlab®). The observed root mean square errors of predictions were 0.14, 0.09, 0.12, and 0.06 for discriminations of mahogany, cedar, andiroba, and curupixá, respectively. The separations of the species obtained based on the difference in the predicted values was at least 0.38. This makes it possible to perform safe discriminations with a very low probability of misclassifying a sample. This method can be considered accurate and fast.

RESUMO O objetivo do trabalho foi avaliar a resistência natural de chapas de partículas orientadas (OSB) confeccionadas com partículas de Hevea brasiliensis Müll.Arg. aderidas com as resinas sintéticas uréia- formaldeído (UF) e fenol-formaldeído (FF), a 5% e 8%, expostas a fungos xilófagos em condições de laboratório. No ensaio acelerado de laboratório as amostras foram submetidas ao ataque dos fungos de podridão-parda Gloeophyllum trabeum (Pers. : Fr.) Murril, Coniophora puteana (Schumach. : Fr.) P. Karst., Meruliporia incrassata (Berk. & M.A. Curtis) Murrill e também aos fungos de podridão-branca, Fomes annosus (Fr. : Fr.) Cooke, Trametes versicolor (L. : Fr.) Pilát, Ganoderma applanatum (Pers.) Pat., Bjerkandera fumosa (Pers. : Fr.) P. Karst. e Phanerochaete chrysosporium Burds. Dentre os fungos de podridão-parda, o Gloeophyllum trabeum causou a maior perda de massa nos corpos-de-prova testados. Dentre os fungos de podridão-branca, Trametes versicolor, Phanerochaete chrysosporium e Ganoderma applanatum causaram as maiores perdas de massa, sem diferença significativa para o Gloeophyllum trabeum. A resina FF proporcionou maior resistência à ação dos fungos nas chapas OSB, o mesmo fato ocorrendo com o maior teor de resina. O fungo Coniophora puteana foi altamente sensível ao tipo de resina aplicado, enquanto o Bjerkandera fumosa demonstrou reduzida ação nas concentrações mais altas de ambas as resinas. O fungo Fomes annosus apresentou degradação insignificante para todos os tratamentos de chapas OSB. ABSTRACT This work aimed to evaluate the natural durability of oriented strandboards (OSB) manufactured with strands of Hevea brasiliensis Müll.Arg. bonded with 5% and 8% of urea-formaldehyde (UF) and phenol-formadehyde (FF) resins, exposed to xilophagous fungi under laboratory conditions. In accelerated laboratory test decay, samples of OSB were exposed to the following fungi: the brown-rot fungi Gloeophyllum trabeum (Pers. ex Fries) Murr., Coniophora puteana (Schumach. : Fr.)P. Karst., Meruliporia incrassata (Berk. & M.A. Curtis) Murrill as well as the white-rot fungi Fomes annosus (Fr. : Fr.) Cooke, Trametes versicolor (L. : Fr.) Pilát, Ganoderma applanatum (Pers.) Pat., Bjerkandera fumosa (Pers. : Fr.) P. Karst. and Phanerochaete chrysosporium Burds. Among the brown-rot fungi, the Gloeophyllum trabeum was the most aggressive, showing the highest loss of mass. Trametes versicolor and Ganoderma applanatum confirmed the preference for broadleave species. All oriented strandboards at lower UF resin contents were more degraded by Phanerochaete chrysosporium, Trametes versicolor, Ganoderma applanatum, Merulia incrassata, Coniophora puteana and Gloeophyllum trabeum, with high rate of loss of mass. Coniophora puteana showed small loss of mass when FF resin was applied. Bjerkandera fumosa showed low loss of mass only at higher resin content. Oriented strandboards exposed to Coniophora puteana showed insignificant OSB degradation.

Oriented strandboard made of pine, cypress and rubberwood. This research evaluated the physical- mechanical properties of oriented strandboards (OSB) using strands of pine, cypress and a mixture of two clones, of rubberwood. The ratio of face to core layer was 1:2:1. Boards measuring 450 x 450 x 13 mm were bonded with 5% and 8% of urea-formaldehyde (UF) and phenol-formaldehyde (FF) resins, based on the dry weight of the particles, with density of 0.75 g/cm 3 . The boards were evaluated according to ASTM D 1037 and compared with CSA O437.0 and ANSI A.208.1 standards. In general, as the resin level increased, mechanical and physical properties also improved, and panels with 8% FF resin showed the best performance. Cypress OSB made with FF resin showed higher mechanical properties, except internal bond than required by aforementioned standards. OSB panels were also dimensionally unstable since water absorption and thickness swelling values were very high. The mechanical properties of rubberwood OSB were higher than required by CSA O437.0 and ANSI A.208.1, except for internal bond, since only panels bonded with 8% of FF resin met the requirements of the CSA O437.0 standard.