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6.8 Pruned Log Quality
Authors: J ParkPublication: NZIF Forestry Handbook, Volume Section 6 – Data collection and projection, pp 8, Dec 2023
Publisher: New Zealand Institute of Forestry
Abstract: Owing to increased understanding and improvements in silviculture by practitioners in the late 1970s, the best pruned logs now being harvested are far superior to the best of a few years ago. However, the poorest pruned logs remain as bad as ever so the gulf between best and worst has widened. The pruned log market has also matured significantly over the last decade as evidenced by large quality-dependent price differentials being realised for pruned log consignments within the same trading period. As a consequence of these developments, demands for quality assurance on pruned log parcels are increasing. While stand records and predictive methods have both improved, sampling at the stand level remains the most reliable and satisfactory option for defining pruned log quality and setting prices. Sampled pruned log quality is defined in two distinct phases. First, basic clearwood potential is indexed for each of the sawing and peeling processes. These results define how well logs have been pruned. The second phase, and essential complement allowing true clearwood potential to be gauged, is definition of the level of random defects such as resin pockets, which cause degrade in the clearwood.