Date of Award

Spring 5-6-2022

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Forest Resources

Advisor

Stephen Shaler

Second Committee Member

Douglas Gardner

Third Committee Member

Ling Li

Abstract

This research focused on the utilization of Maine Eastern spruce and balsam fir for veneer production. Maine currently has no manufacturers of or products using structural veneer. The diversification of markets for Maine’s softwoods has been identified as a route to increase the resilience of the forest-based economy. Veneer production technology has improved significantly since the last look at Maine spruce veneer (1969), justifying the reinvestigation of Maine spruce-fir veneer. The objective of this research was to provide information on the yield of processing veneer and the quality of said veneer. A sample size of 37 Eastern spruce and 38 balsam fir logs ranging in top end diameter from 6 to 14 inches and averaging 10 inches was selected. No differences in (green) specific gravity from published values were found. Species differences were noted in the radial growth rate measure of rings per inch (RPI). Eastern spruce had a higher RPI (14.8) than balsam fir (8.8) indicating a slower average growth rate. Additionally, the juvenile wood (JW) radius, the radius from the pith to 20 years of age, was smaller in Eastern spruce (2.0 inch) than balsam fir (2.7 inch). These JW radii correlated to 26% JW for balsam fir and 17% JW for Eastern spruce. The selected logs produced 283 sheets of eastern spruce veneer and 291 sheets of balsam fir veneer. The average yield of veneer was around 60% for both species. The previous study on spruce veneer reported yields of 40% for a larger average sample size (14.5 inches). For both studies yield was defined as the amount of full sheet material (dry) in relation to the total log volume (green). Veneer quality was evaluated through visual grading and stress wave propagation timing which estimates modulus of elasticity (MOE). For visual grading, standards: PS1-19 Structural plywood and ANSI/HPVA HP1-2016 were referenced. For PS1-19, over 80 % of veneer sheets for both species were grade C veneers. The majority of remaining veneers (10 + %) were grade D with little high grade material free of knots found. Similar results were found for the ANSI/HPVA HP1-2016 standard. Over 65% of veneers for both species had grade L characteristics. Higher amounts of the veneer grades around grade L were found for this standard. Over 15% of veneer sheets for both species had grade M (the lowest grade) characteristics. The lower grade veneers (C and D, L and M) for both standards are acceptable for use in core plies of structural and hardwood decorative plywood. For veneer MOE, Eastern spruce veneer had a higher mean MOE (1.66 x10^6 PSI) than balsam Fir (1.39 x10^6 PSI). Additionally, veneer containing JW had significantly lower MOE values than mature veneers. The average MOE of veneers peeled from the juvenile portion of the logs was 1.42 x10^6 and 1.30x10^6 PSI, for Eastern spruce and balsam fir, respectively. Whereas the remaining (mature) veneers (i.e., past JW radius) had averages of 1.73 x10^6 PSI and 1.45 x10^6 PSI, for Eastern spruce and balsam fir, respectively.

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