The flexural properties of young Pinus elliottii × Pinus caribaea var. hondurensis timber from the Southern Cape and their prediction from acoustic measurements

Abstract

The objectives of this study were to determine the bending strength and stiffness properties of young Pinus elliottii × P. caribaea var. hondurensis timber from the Southern Cape, South Africa, and to evaluate the predictability of these properties from acoustic measurements on standing trees, logs and their sawn boards. The timber has good bending strength (MOR) properties but the mean stiffness (MOE_stat) was significantly lower than that required for structural-grade timber. The mean MOE_stat was also about 30% lower than a P. radiata control sample. The MOE_stat of sawn boards could be predicted from acoustic stress wave measurements on standing trees with a correlation (r) of 0.48 and from acoustic resonance frequency measurements on sawn boards with a correlation of 0.85. The MOR of sawn boards was not significantly correlated with acoustic stress wave measurements on standing trees and only moderately correlated with acoustic resonance frequency measurements on sawn boards (r = 0.45).

Keywords: acoustic stress wave, modulus of elasticity, modulus of rupture, Pinus elliottii × P. caribaea var. hondurensis

Southern Forests 2011, 73(3&4): 137–147