TMP PROPERTIES OF RADIATA PINE FAMILIES SEGREGATED BY TRACHEID LENGTH AND DENSITY ― A PRELIMINARY INVESTIGATION

摘要

The impact on variations in radiata pine wood density and tracheid length for paper strength qualities and thermomechanical pulp (TMP) energy requirements for within trees, between trees and between wood classes has been assessed. Genetic variation in a structured field planting has been demonstrated. Wood samples were selected from families representing quadrant extremes of tracheid (fibre) length-density: Two trees representative of each category (mostly from different families) were harvested and compared with a single tree (80055 cross). An excellent correlation was found between the density of discs and whole tree woodchip basic density. The low density-long fibre class (family 12349 x 12038) wood required significantly less refining energy and had better pulp strength properties than the other samples. Restriction of dilution water to the refiner housing flat zone during processing of some of the wood samples, resulted in pulps of reduced fibre length and inferior strength properties. Although paper strength differences were found between P. radiata samples from trees of different density and tracheid length, definitive trends were inconclusive because of the limited data available. More work is required to substantiate the preliminary findings.