Canadian Forest Service Publications
Wood mechanical properties and discoloured heartwood proportion in sugar maple and yellow birch grown in New Brunswick. 2016. Duchesne, I.; Vincent, M.; Wang, X.D.; Ung, C.-H.; Swift, D.E. BioResources 11:2007-2019.
Issued by: Laurentian Forestry Centre
Catalog ID: 36535
CFS Availability: PDF (request by e-mail)
Rising interest in using wood in non-residential multi-story building structures opens up new opportunities for utilising low-grade hardwoods. The primary objective of this study was to evaluate the geographic variation in modulus of elasticity (MOE) and modulus of rupture (MOR) of sugar maple and yellow birch wood in relation to stand and tree characteristics for two regions in New Brunswick, Canada. Mixed effects statistical models were developed to test the effects of stand, tree, and wood sample variables. A second objective was to examine geographic variation in heartwood discolouration in relation to stand and tree characteristics. Between-tree differences (trees nested within sites) accounted for 44% and 35% of the total variation in yellow birch (MOE and MOR, respectively) and for 69% and 60% of total variation in sugar maple. The fixed effects explained only a very small part for the variation in MOE and MOR in the sugar maple date (10% for MOE and 5% for MOR). For sugar maple, mechanical properties (MOE and MOR) at 50% of the radius were considerably lower than those close to the bark, but this radial variation was not noteworthy for yellow birch. Discoloured heartwood proportion had no significant effect on wood mechanical properties.
Plain Language Summary
The results of this study showed that tree provenance did not affect wood mechanical properties in sugar maple and yellow birch. In sugar maple, mechanical properties were weaker near the heartwood. In yellow birch, a direct relation was observed between tree age and the proportion of heartwood. Researchers also observed that heartwood proportion had no significant effect on wood mechanical properties.
One of the specific objectives of this study was to compare variations in the mechanical properties of these two hardwood species, which are found in two different ecological regions of New Brunswick (central highlands and northern highlands).
The mechanical properties studied were the modulus of elasticity (MOE) and the modulus of rupture (MOR). The MOE is a measure of wood deformation whereas the MOR is a measure of wood maximum resistance right to the point of rupture.