Effects of Specific Gravity and Lignin Content on the Pulp Yield of Loblolly Pine, 2007 Engineering, Pulping & Environmental Conference

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This research is directed at developing a critical quantitative understanding of the effects of wood density (chip specific gravity) and wood composition (cellulose, hemicellulose and lignin) on the kraft pulp yield of 13-year-old loblolly pine trees (Pinus taeda) grown as part of a genetic selection study. Both bleachable grade (Kappa 30) and linerboard grade (Kappa 100) pulps were made from eighteen trees selected for combinations of wood specific gravity and cellulose:hemicellulose:lignin ratios. Statistical analysis indicated that digester pulp yield had a significant degree of correlation with wood xylan content and cellulose to lignin ratio but was not strongly correlated to specific gravity. Near infrared (NIR) spectra were collected from wood samples and correlated with the pulp yields. The analysis for screened kraft pulp yield and total kraft pulp yield at Kappa 30 provided strong calibration statistics and suggests that NIR spectroscopy could be used to estimate the bleachable grade pulp yield of Pinus taeda whole-tree samples. Calibrations for screened pulp yield and total pulp yield at Kappa 100 were weaker and could not be expected to provide accurate estimates of screened or total pulp yield for the linerboard grade pulps.