Effects of loblolly pine tree age and wood properties on linerboard-grade pulp yield and sheet properties: Part 2
Results are presented on the relationships among loblolly pine tree age and wood characteristics and the properties of pulp obtained when the trees were chipped and pulped. We selected 13-year-old and 22-year-old loblolly pine trees (18 of each) to represent specified ranges of specific gravity and lignin content. The trees were further characterized by chemical analysis, near infrared (NIR) spectroscopy, and SilviScan analysis of fiber dimensions and properties before being pulped by the kraft process. Handsheets formed from the resulting pulps were characterized in terms of sheet properties that are important for linerboard grades. Multiple regression analysis was then used to identify wood characteristics that most influenced sheet properties and to derive equations relating sheet properties to tree age, specific gravity, and chemical composition. We also developed calibrations so that sheet properties could be predicted from NIR spectroscopic analysis of wood. Nearly all differences in properties of pulps made from 13- and 22-year-old trees were attributable to differences in fundamental wood properties. Sheet properties could be estimated by measuring their near NIR spectra.