Compression and flexural properties of plantation-grown Eucalyptus pellita in Borneo, Malaysia. Potential for structural timber end use

ABSTRACT

Plantation-grown Eucalyptus pellita in Sabah, Malaysia, was analysed for compression and flexural properties to assess the potential for solid-timber and engineered wood product end uses. It is necessary to consider not only the volume of wood produced in a plantation but also the wood quality, particularly those aspects important for end-product performance. Tree volume is readily measured from height and diameter at breast height using appropriate form factors. This paper discusses the compression, strength and stiffness of E. pellita compared with tropical hardwood species, and variation within trees and at different ages (7–23 years). Small clearwood test samples obtained from radial positions within log heights were subjected to analysis of compression parallel to grain and three-point bending according to ISO 13061-4, 2014. Results indicate that plantation-grown E. pellita in the tropics has potential for structural-use applications. The average basic density across the trials was 658 kg m⁻³, while the bending strength for all trials was in the range of 11.7–15.5 GPa for modulus of elasticity and 96.3−120.1 MPa for modulus of rupture, and the compression strength parallel to grain ranged from 52.3 to 67.8 MPa. Mean mechanical strength increased from pith to bark and from the butt log to the top log. Because the wood-processing sector in Malaysia is transitioning from reliance on a harvest of mixed tropical hardwood towards plantation-grown species, these results indicate that plantation-grown E. pellita meets the structural requirements of strength and stiffness.

KEYWORDS:

• basic density
• Borneo
• Eucalyptus pellita
• kraft pulp yield
• modulus of elasticity
• modulus of rupture

Acknowledgements

This study was conducted as part of the Solid Wood Project of the Borneo Forestry Cooperative (www.borneoforestrycoop.com), and the support of the member companies for access to the resource and financial support is gratefully acknowledged. The authors expressly thank the Forest Research Centre at the Sabah Forest Department for access to material in KB96/22. Many thanks are extended to Mawi Alwi for assistance with the mechanical testing. YJ gratefully acknowledges a postgraduate scholarship from USC to undertake the study. The authors thank anonymous reviewers, the comments of whom helped significantly improve the paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the University of the Sunshine Coast [PhD studentship] for YJ.