Stem damage of lodgepole pine clonal cuttings in relation to wood and fiber traits, acoustic velocity, and spiral grain

Abstract

Eight clones from a 16-year-old field trial of clonal cuttings of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) were analyzed for growth, growth pattern, and stem damage in the field. In addition, wood and fiber traits (acoustic velocity [AcVel] and spiral grain) were analyzed and wood density, microfibril angle, modulus of elasticity, and radial fiber diameter (FibDR) determined from SilviScan analyzes. Two clones with considerably more bent, broken, and leaning stems differed from the other clones in terms of microfibril angle and modulus of elasticity (MOE) in the outermost annual rings. FibDR and, to some extent, MOE in the outermost annual rings were negatively correlated with the frequency of bent, leaning, or broken stems, while microfibril angle (MFA) was positively correlated. AcVel was negatively correlated with both MFA and the frequency of bent, broken, and leaning stems. We conclude that AcVel could be used as an effective tool to predict severe stem damage and determine stem strength in the field instead of using costly lab-based SilviScan measurements of microfibril angle. If developed further, this approach could be used for large-scale screening of progeny tests when selecting for stem strength.

Keywords:

• fiber diameter
• microfibril angle
• modulus of elasticity
• stem bow
• stem damage
• stiffness
• wood density

Acknowledgments

Thanks are also due to personnel at Svartberget Research Station, the Unit for Field-based Forest Research, Swedish University of Agricultural Science for field measurements, and personnel at Innventia AB for skillful SilviScan analyzes and valuable advices when interpreting the data.

Funding

This work was supported by the Association for Forest Tree Breeding [grant number 209].

Additional information

Funding

Funding: This work was supported by the Association for Forest Tree Breeding [grant number 209].