Effect of harvesting season, system and equipment on in-forest Pinus radiata bark removal in Australia and New Zealand

ABSTRACT

Depending on the point of view of the participants in the forest-to-customer supply chain, the presence of bark can be considered as either a benefit or a cost. Understanding which factors affect bark removal should help with managing bark quantities, and the design of harvesting systems and equipment. Over 4000 stems and logs in 11 studies were measured in Australia and New Zealand using digital photos and a line intercept method to determine the amount of bark removed during normal operations. Among other things, we have been able to show that bark removal is greater in spring than winter, with tree-length systems than cut-to-length systems, and with mechanized processing rather than manual processing systems. We were also able to show that the greatest portion of bark removal occurs during felling and extraction with tree-length operations, with a small proportion occurring during delimbing and bucking. There was limited and weak evidence that bark removal may differ with location on pine stems. Finally, we were able to show that the number of knives on a processor head can affect bark removal, although we would recommend that further research be carried out on this topic, since the results ran counter to expectations.

KEYWORDS:

• Bark loss
• mechanized processing
• harvesting season
• processor head design

Acknowledgements

Thanks are extended to Wespine Industries Ltd, C3 Ltd, and Timberlands Ltd for providing data collection opportunities on their sites. Thanks are also extended to Rick Mitchell and Pat Hodgkiss for undertaking the bulk of the field work associated with this project.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the New Zealand Forest Growers Levy Trust.