Pruned log index

A Pruned Log Index (PLI), derived from measurements of log size and shape and the size of the defect core, has been developed as an absolute measure of pruned sawlog quality. It is based entirely on measurable log variables routinely acquired under either of two established pruned log analysis systems. Being dependent on accurate and detailed measurements, PLI is of higher precision than other existing forms of pruned log classification. Consequently its application should be limited to real logs only (other less precise measures are more appropriate for predicting future log quality). The index was developed and validated with the assistance of the pruned log sawing simulator SEESAW. Simulation was used in preference to the real sawing results available in order to avoid the confounding influences of sawmill variables. This simulation approach also allowed the performance of trial formulae to be examined under three distinct sawing systems. Initial derivation of formulae was intuitive, based on previous experience, and all formulae included terms for log size, log shape, and defect core size. Trial indices were regressed against conversions to clears grades from SEESAW simulations using two sets of real log data from the SEESAW "library". Set 1 consisted of 74 pruned Pinus radiata D. Don logs, originally acquired through sawing studies, and was used to explore and evaluate trial formulae. Set 2 consisted of 15 logs, originally acquired through log cross-sectional analysis, and was used for validation