Influência dos extrativos e da relação cerne/alburno nas análises da madeira por espectroscopia de infravermelho próximo para produção de celulose

• Autor(a) principal: Lopes, Onel Reis
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3049
• topic: Eucalipto; NIRS; Extrativos; Alburno; Cerne; Eucalyptus spp.; NIRS; Extractives; Sapwood; Heartwood; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS

The objective of this work was evaluating the influence of Eucalyptus spp extractives quantity and nature and heartwood/sapwood ratio on wood technological characteristics prediction by near infrared spectroscopy (NIRS). Sixty four trees of different species and ages, planted in different areas and cultivated in different water, nutrition and sunlight availability conditions, were harvested in order to obtain wood with different contents of extractives and heartwood/sapwood ratios. For each sample, discs were collected at the chest height diameter (DAP =1.3 m), the heartwood and sapwood were separated, ground to sawdust of proper coarseness and analyzed for their contents of extractives in hot water, ethanol:toluene (1:2) and dichloromethane. These same samples were analyzed by NIR. The whole trees were chipped and analyzed for basic density, total lignin and pulping yield and these characteristics were calibrated against the NIR spectra obtained from the DAP sawdust either unextracted or extracted with hot water, ethanol:toluene (1:2), and dichloromethane. It is concluded that wood components extraction efficiencies decrease in the order ethanol:toluene (1:2) > hot water> dichloromethane. The NIR spectra of the unextracted and solvent extracted wood samples were only slightly different among themselves, but the correlation values (R) obtained in the multivariate calibration were influenced by the solvent extraction treatments. For example, the highest NIR calibration R value (0.80) for pulping yield was obtained for the unextracted wood sample. On the other hand, the highest R value (0.93) for wood density was achieved for ethanol:toluene (1:2) and dichloromethane extracted wood samples. The removal of extractives from heartwood with dichloromethane improved the calibration model, raising the R value to 0.95 for wood basic density. For all samples studied, the NIR correlations show different values but the principal components were the same. The difference in wood extractive composition within the heartwood and sapwood interfered with the NIR multivariate calibration.