Anatomia do lenho e do carvão de espécies arbóreas do Cerrado no Estado de São Paulo, Brasil
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Data
2010-08-27
Autores
Gonçalves, Thaís Alves Pereira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A Antracologia é uma ciência que se baseia na anatomia da madeira para realizar a análise e identificação de carvão vegetal. No Brasil, ela visa tradicionalmente obter dados paleoecológicos e paleoetnobotânicos, mas também conservacionistas e tecnológicos. As análises antracológicas são possíveis porque a estrutura do lenho se mantém no carvão, entretanto, variações morfométricas podem ocorrer. O presente estudo visa contribuir para um melhor entendimento do efeito da carbonização no lenho através da análise estrutural da anatomia antes e após carbonização. A escolha de espécies do cerrado deveu-se ao forte impacto que este bioma sofre pela devastação e, principalmente, pelo uso de suas espécies para a produção de carvão vegetal. A anatomia do lenho e do carvão obtido a 400ºC foram analisadas em amostras de Copaifera langsdorffii, Dalbergia violacea, Dimorphandra mollis, Stryphnodendron polyphyllum, Caryocar brasiliense, Couepia grandiflora, Tapirira guianensis, Qualea grandiflora, Vochysia tucanorum e Pouteria torta, todas provenientes do cerrado e apresentando tipos anatômicos distintos. Todos os resultados quantitativos foram comparados estatisticamente. A contração anisotrópica nos carvões foi evidenciada principalmente na redução do diâmetro tangencial dos vasos, que ocorreu em 70% das espécies, mas não foi o suficiente para aumentar significativamente sua frequência; o diâmetro da abertura das pontoações intervasculares praticamente se manteve; a frequência dos raios aumentou ligeiramente; a altura e a largura dos raios variaram bastante, sendo que os raios mais largos contraíram mais que os estreitos; o parênquima axial manteve, no carvão, características semelhantes às do lenho; as fibras dos carvões perderam a distinção das camadas das paredes celulares presentes no lenho, mas mantiveram dimensões semelhantes...
Anthracology, or charcoal analysis, is a science based on wood anatomy. In Brazil it traditionally studies palaeoenvironment and palaeoethnobotany, as well as nature conservancy and forestry technology. Anthracological analyses are possible due to the maintenance of wood structure in charcoal. The present study aims to contribute to a better knowledge of carbonization on wood anatomy. Fresh and charred cerrado woods samples were analyzed. The Brazilian cerrado is highly impacted by devastation, while its species are widely used for charcoal production. The latter were charred under 400ºC. The selected species present different anatomical characteristics: Copaifera langsdorffii, Dalbergia violacea, Dimorphandra mollis, Stryphnodendron polyphyllum, Caryocar brasiliense, Couepia grandiflora, Tapirira guianensis, Qualea grandiflora, Vochysia tucanorum, and Pouteria torta. All the quantitative data between wood and charcoal were statistically analyzed. The anisotropic pattern of contraction in charcoals was evident as 70% of the species presented a reduction in vessels tangential diameter. Vessel frequency increase, however, was not statistically significant. Intervessel pits apertures diameters were very closely between wood and charcoal. Rays frequency slightly increased; rays height and width were extremely variable. Larger rays contract more than narrow ones. Axial parenchyma retained, in charcoal, the same dimensions and shape of wood. Charcoal fibres presented indistinct cell wall layering, but retained similar dimensions of wood fibres. Carbonization under 400ºC caused only few changes between wood and charcoal, corroborating the assumption that wood anatomy and anthracology are two closely related sciences
Anthracology, or charcoal analysis, is a science based on wood anatomy. In Brazil it traditionally studies palaeoenvironment and palaeoethnobotany, as well as nature conservancy and forestry technology. Anthracological analyses are possible due to the maintenance of wood structure in charcoal. The present study aims to contribute to a better knowledge of carbonization on wood anatomy. Fresh and charred cerrado woods samples were analyzed. The Brazilian cerrado is highly impacted by devastation, while its species are widely used for charcoal production. The latter were charred under 400ºC. The selected species present different anatomical characteristics: Copaifera langsdorffii, Dalbergia violacea, Dimorphandra mollis, Stryphnodendron polyphyllum, Caryocar brasiliense, Couepia grandiflora, Tapirira guianensis, Qualea grandiflora, Vochysia tucanorum, and Pouteria torta. All the quantitative data between wood and charcoal were statistically analyzed. The anisotropic pattern of contraction in charcoals was evident as 70% of the species presented a reduction in vessels tangential diameter. Vessel frequency increase, however, was not statistically significant. Intervessel pits apertures diameters were very closely between wood and charcoal. Rays frequency slightly increased; rays height and width were extremely variable. Larger rays contract more than narrow ones. Axial parenchyma retained, in charcoal, the same dimensions and shape of wood. Charcoal fibres presented indistinct cell wall layering, but retained similar dimensions of wood fibres. Carbonization under 400ºC caused only few changes between wood and charcoal, corroborating the assumption that wood anatomy and anthracology are two closely related sciences
Descrição
Palavras-chave
Anatomia vegetal, Carvão, Antracologia, Wood anatomy, Anthracology, Charcoal, Woody species
Como citar
GONÇALVES, Thaís Alves Pereira. Anatomia do lenho e do carvão de espécies arbóreas do Cerrado no Estado de São Paulo, Brasil. 2010. xii, 111 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas de Botucatu, 2010.