Vessel morphological evaluation of Acacia melanoxylon wood

• Autor(a) principal: Rodrigues, Catarina
• Data de Publicação: 2007
• Outros Autores: Santos, António J., Tavares, Mário, Anjos, O.
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.11/2265
• topic: Acacia melanoxylon; Wood morphology; Vessel

In this paper we analyze the transversal variation of Acacia melanoxylon R. Br. wood porosity, using five trees with 40cm dbh collected in the Ponte de Lima region, in northwestern Portugal. Variation of porosity, vessel area, width and density were used to evaluate tree vessel variation, in order to relate it with other wood properties. Each value of these variables represents a mean of 60 vessels measurement. We collected five wood disks at the bottom, 5, 15, 35 and 65% of total height, and commercial top of those five trees, in order to acquire three radial cores at 10, 50 and 90% near the pith, and in north and south directions. We found great variability along the tree concerning the axial and radial positions. Porosity is higher near the bottom and lower at the top; vessel number varies inversely. Vessels width and density are similar at the different height levels. Radial variation show that porosity, vessel area and vessel width all increase, and density decreases, with distance to the pith. Principal components analysis was used to investigate the differences in vessel characteristics and levels in the trees, as well as their interaction. This methodology allowed us to determine how close, or how independent, the study variables were. We conclude there is a group of vessel morphologic characteristics which depend strongly on each other – porosity and vessel area and vessel number are negatively correlated with the other. The variation between North and south direction is not significant, because the values are very similar and the trees don’t present a higher eccentricity.