Abstract

TARCISIO LIMA, José; DE OLIVEIRA RIBEIRO, Alessandra  and  REZENDE PINTO NARCISO, Carolina. Microfibril angle of Eucalyptus grandis wood in relation to the cambial age. Maderas, Cienc. tecnol. [online]. 2014, vol.16, n.4, pp.487-494.  Epub Aug 21, 2014. ISSN 0718-221X.

The microfibril angle (MFA) of wood is an important feature, which helps to explain the physical and mechanical behaviour of wood in use. It has been little investigated for wood produced in Brazil, mainly for mature trees. Thus, the objective of this study was to analyze the MFA of Eucalyptus grandis at age 25 years in relation to the cambial age. One disk was cut from the base of the stem from each of three trees, where growth rings were marked. From a central strip 3,0 cm wide, 1 cm³ blocks were removed from each growth ring. After sectioned on the tangential face with a sliding microtome, sections of 8 μm thick were macerated. The individual fibres were observed by polarized light microscopy for measurement of MFA. According to the results, i) the MFA decreased from 29,3° (ring nº 1) to 18,9° (ring nº 25); ii) MFA can be estimated by the cambial age - a, according to the equation MFA = 28,1 - 0,35 × a, with R² = 94,7%.

Keywords : Microfibril angle; Eucalyptus grandis; cambial age.

        · text in English     · English ( pdf )