Relationships between microfibril angle, modulus of elasticity and compressive strength in Eucalyptus wood

Abstract

Many traits are known to be important in determining the value of Eucalyptus wood as sawn tim-ber. The commercial importance of the microfi bril angle (MFA) for wood quality is well established for a range of softwoods, but is less clear for hardwood species. For instance, the relationships of MFA with wood stiffness and compressive strength are unknown in Eucalyptus. Therefore, the aim of this study was to evaluate the correlation between MFA and the modulus of elasticity (Ec0,m) in compres-sion parallel to grain and compressive strength (Fc0,k) using juvenile wood of Eucalyptus grandis from fast-growing plantations. The correlation between wood stiffness and compressive strength was high (0.91). The cellulose microfi bril angle presented a correlation of -0.67 with wood stiffness and of -0.52 with compressive strength in Eucalyptus juvenile wood. MFA was found to be important in de-termining the mechanical behaviour of wood and appears to be a useful parameter to indicate wood stiffness and strength in juvenile Eucalyptus from short-rotation plantations.