WOOD DENSITY AND KRAFT FIBRE AND PULP PROPERTIES OF FOUR

Four native provenances of Pinus radiata D.Don were sampled in a common environment for studying wood density (as chip density), kraft pulp yield at Kappa number 302, 10 pulp fibre properties, and four handsheet properties. Each provenance sample comprised a nominal 30 unrelated trees. Separate wood specimens were taken to represent toplog and slabwood material respectively. Within each of the eight provenance/ wood-zone subclasses the trees were allocated at random to give duplicate bulked chip samples. Use of four refining treatments gave further replication and allowed various handsheet properties to be evaluated in relation to density, tear index, and tensile index. The various properties were similar for the four provenances (Ano Nuevo, Monterey, Cambria, and Guadalupe), except in the Guadalupe toplog material. Chip densities for the Guadalupe toplog and slabwood samples were surprisingly similar, and Guadalupe toplog fibres were short, slender, of low coarseness, stiff (high collapse resistance), and thus present in large numbers compared with those of the other toplog pulps. Opportunities for tree breeding could, therefore, involve selecting Guadalupe trees with high density and large numbers of slender tracheids of low coarseness in the corewood. Such selection should substantially improve corewood properties for both solid-wood products and pulping. Verification of the distinctive tracheid properties found in Guadalupe marterial is now needed