Pre-processing prediction of wood quality in peeler logs grown in northern New South Wales

Summary

Pinus elliottii (slash pine), P. taeda (loblolly pine) and Eucalyptus saligna (Sydney blue gum) logs grown in northern New South Wales were acoustically sorted into three wood stiffness classes. Veneers were peeled from the class-designated nine log batches and plywood boards then manufactured. In all species, the stiffness of the plywood boards was found to be closely related to the average recorded acoustic velocity of log batches. The average stiffness ranking of the plywood boards across species was E. saligna > P. elliottii > P. taeda. Regardless of species, sound velocity along logs reflected sound velocity measurements of corresponding peeler cores, suggesting that the average log acoustic signature may be a means towards managing problematic corewood stiffness. Mill studies confirmed the robustness of the mathematical relationship between sound velocity and wood stiffness. The implications are that acoustic tools have the potential to minimise yield of low-quality product during plywood manufacture. In turn, forest growers have the opportunity to use wood quality information, from both non-destructive stress wave (acoustic) technology and micro-processing studies on the current crop, to assist with silvicultural decisions for future new or replacement crops. Growers and processors should explore ways to integrate wood quality data into forest management information systems, linked to differential pricing arrangements, to maximise economic returns.

Keywords:

• log grade
• wood properties
• wood density
• wood strength
• juvenile wood
• quality
• grading
• outturn
• instruments
• acoustic properties
• plywood
• Pinus elliottii
• Pinus taeda
• Eucalyptus saligna