Evaluation of the Hitman PH330 acoustic assessment system for harvesters

Abstract

Reductions in Pinus radiata D. Don. (radiata pine) clearfell age have increased the juvenile wood proportion in sawlogs, increasing the need to segregate low modulus of elasticity (MOE) material early in the supply chain to avoid the costly processing of low-value, non-structural boards. In Australian radiata pine plantations, variability in MOE is greater between trees than between stands, requiring tests of individual trees to identify those with low MOE. Time of flight of a sound wave in a tree or log is known to be well-correlated to its MOE. The trial examined the ability of a newly developed acoustic assessment tool, the Hitman PH330 (PH330) supplied by Fibre-gen Limited, fitted to a harvester head, to identify and segregate low MOE sawlogs during a cut-to-length harvesting operation in a radiata pine plantation. The impact of using the tool on the harvester’s productivity was also examined. There was a reduction in the mean productivity of the harvester when using the PH330 compared with normal operations not using the PH330 but it was not significant. Mechanical MOE testing showed that boards cut from sawlogs which the PH330 identified as structural, had significantly greater mean MOE than boards from non-structural sawlogs, demonstrating the PH330 was able to separate high and low MOE sawlogs.

Keywords:

• forestry
• cut-to-length
• radiata pine
• modulus of elasticity
• timber harvesting

Acknowledgements

This work was supported by Fibre-Gen, Wespine, Forestry Corporation of New South Wales, Forestry South Australia, Forest Products Commission of Western Australia, Plantation Logging Co. and the CRC for Forestry. Special thanks go to Steve Ardille (formerly) of Wespine for contributing the data from the mill trial and providing comments on the analysis for the original study report which he was a co-author of and upon which this journal article is based.