Properties of veneer and veneer-based products from genetically improved white spruce plantations.

摘要

This study examined the suitability of genetically improved fast-growing and short-rotation plantations for veneer-based products. The materials came from a 36-year-old white spruce (Picea glauca) half-sib progeny/provenance trial located in two regions (sites) of Quebec, Canada. A total of 270 sample trees were collected for the study, 130 trees from St. Ignace in the Gaspe Region and 140 trees from Valcartier near Quebec City. Veneer from the Valcartier site had a mean wood density of 0.353 g/cm3 and a mean modulus of elasticity (MOE) of 9.48 GPa (1.375 million psi). Veneer from the St. Ignace site had a mean wood density of 0.345 g/cm3 and a mean MOE of 8.05 GPa (1.167 million psi). The differences in veneer wood density and MOE between the two sites were statistically significant. Compared to other Canadian species commonly used for veneer products, the genetically improved fast-growing and short-rotation white spruce yielded considerably lower veneer stiffness. The plantation-grown white spruce veneer from both sites was knotty. Ninety-eight percent of the veneer was classified as visual grade C. The visually graded veneer would be suitable for sheathing grade plywood. With proper stress grading, 14% of the white spruce veneer was suitable for 12.41 GPa (1.8 million psi) grade laminated veneer lumber (LVL), and another 24% of the veneer was suitable for a lower 10.34 GPa (1.5 million psi) grade of LVL, or as core plies for LVL manufacture. The remaining 62% of the stress-graded veneer was suitable for sheathing grade plywood..