Recovery of clear lengths from pruned Pinus radiata sawlogs

Results from analysis of 165 pruned Pinus radiata D. Don butt logs, drawn from 11 forests and converted by one standardised sawpattern, were used to introduce the concept of evaluating sawn produce by recoverable clear lengths. Samples represented the range of straight pruned log types expected from the "Transition Crop". Clears and clearcuttings were expressed as distributions, by percentage of round log volume, in nine nominated clear length classes. The effects of extracting clear lengths on over-all conversion, consequent volumes of defecting waste, and numbers of crosscuts to be made on boards were also determined. Volumes in each clear length class, defecting waste, and numbers of crosscuts required were all found to be predictable and have been modelled. The predictive models derived adequately identified the clearwood which could be sawn from the range of pruned log types investigated. Comparisons with earlier results showed the clearwood potential of a large proportion of the "Transition Crop " logs was poorly represented under standard timber grades. Therefore it is proposed that appraisal of pruned sawlogs by their recoverable clearwood becomes standard practice. This would provide both an alternative and a complement to evaluations by timber grades, and promote better under-standing of the potential of various pruned log types for sawn timber