Forest Investment Account

Abstract of FII Project R2003-220

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Guidance for Rigging Backspars in Cable Logging

Author(s): Lyons, C. Kevin (University of British Columbia)
Subject: Forestry, Technology/GIS/Modeling/Remote Sensing
Series: Forest Investment Account (FIA) - Forest Science Program


Partial retention silviculture systems, where live trees are retained after harvesting, are becoming common in British Columbia. If cable logging is used to harvest a cutblock with partial retention, it is often necessary to use backspars to ensure there is sufficient lift to prevent damage to the residual trees. The backspar system consists of a live tree, guylines, skyline strap, and stumps used to anchor the guylines. Unexpected events can cause backspars to fail, where falling cables and rigging pose a hazard to workers. Since stumps are used to anchor the guylines, the placement of the guylines is rarely optimal. If one guyline is significantly shorter or longer than the other guylines then it is possible components of the backspar system may reach their design load unexpectedly. This project will examine how the components of the backspar system interact and will provide guidance for the appropriate tensions in the guylines. With this knowledge workers will be able to better recognize hazardous situations and take appropriate actions to ensure their safety.

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Updated September 08, 2005 

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