Clonal variation in wood-, chemical-, and kraft fibre and handsheet properties of slabwood and top-logs in 27-year-old radiata pine

Broad sense heritabilitics of kraft pulp handsheet properties were high for both toplog and slabwood pulps from 27- and 28-year-old clonal ramets. Heritabilities were moderate to high for kraft Fibre length and cross section dimensions. Heritabilitics were moderate for glucose content and pulping yield. Heritabilities for whole-tree wood density and tracheid dimensions were very high, and moderate for whole-tree microfibril angle. When toplogs, 'midlogs and toplogs', and slabwood were compared, 'midlogs and toplogs' had chip density and fibre length values that were intermediate between the low toplog values and high slabwood values. Toplog and 'midlog and toplog' handsheet values were very similar, and very different from slabwood handsheet properties. There was a large amount of clonal variation for a given woodtype in all properties. The range of clonal variation for a given woodtype was similar in magnitude to differences between woodtypes for wood density, glucose content, pulp yield, sheet density, tensile index, and tear index. Segregation of wood chips from monoclonal blocks could realise differentiation of kraft pulp properties to a similar extent as the current practice of segregation on wood type.