Sampling criteria and interrelationships involving tree age and wood and pulp-fibre properties in 50 individual radiata pine trees

摘要

Two sets of 25 trees were taken, from a preselected population of 200, at age 13 years (Tree-set13) and 15 years (Tree-set15). These 200 trees represented eight half-sib progeny of each of 25 trees that had been selected for growth rate, tree form, and extremes of tracheid wall thickness and perimeter. From these 200 trees, 25 were selected to cover an extreme range of tracheid wall thickness and perimeter, (Tree-set13). Two years later the 25 trees of Tree-set 15 were selected from the remaining 175, firstly for tracheid length and secondly for tracheid perimeter and wall thickness. Effects of Tree-sets and interrelationships involving a wide range of individual-tree wood, and kraft and pressurised mechanical pulp (PRMP) fibre properties are assessed through determining the following: 1. Wood and chip density, chemical composition, compression wood content, tracheid cross-section dimensions and microfibril angle. 2. Kraft and PRMP fibre dimensions and collapse, and kraft handsheet density, and wood and chip density, and tracheid cross-section dimensions. The individual-tree density, tracheid dimensions and coarseness, MFA and chemical properties of Tree-set13 and Tree-set 15 were influenced, to greater or lesser extents, by a 2-year tree-age difference and /or different tree selection processes, as expected. Furthermore, a two-unit kappa number difference between the individual-tree kraft pulps of Tree-set13 (28.7) and Tree-set15 (26.3) is large enough to cause highly significant changes in fibre collapse and wall area (coarseness), and handsheet density.