Selected mesostructure properties in loblolly pine from Arkansas plantations

Abstract

Design properties of wood are currently established at the macroscale, assuming wood to be a homogeneous orthotropic material. The resulting variability from the use of such a simplified assumption has been handled by designing with lower percentile values and applying a number of factors to account for the wide statistical variation in properties. With managed commercial forests geared toward rapid growth and shorter rotation harvests, wood products now contain significantly fewer and more widely spaced growth rings, further stretching the validity of the assumption of homogeneous behavior. This chapter reports on preliminary results of a study on measuring the property differences and variability of earlywood and latewood (mesostructure) samples from a commercial loblolly pine plantation. Novel testing procedures were developed to measure properties from 1-by 1-by 30-mm mesostructure specimens. Properties measured included longitudinal modulus of elasticity, shear modulus, specific gravity, and microfibril angle. The test results showed dramatic differences in the properties of adjacent earlywood and latewood, differences that are believed to influence product performance. As important as the data that documents the property differences is the information on the variability of these properties.

Citation

Kretschmann, David E.; Cramer, Steven M.; Lakes, Roderic; Schmidt, Troy. 2006. Selected mesostructure properties in loblolly pine from Arkansas plantations. Characterization of the cellulosic cell wall. Ames, Iowa : Blackwell Pub., 2006: ISBN 2005016442: pages 149-170.