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Dangerous tree struck chokerman during cable yarding

Date of incident: May 2014
Notice of incident number: 2014136050046
Employer: Logging company

Incident summary
A forestry operation's prime contractor was performing uphill cable yarding. The worker who was performing chokerman activities had set chokers (loops of wire cable) around three felled trees. As the operator of the cable yarder attempted to yard (pull in) the logs, the yarder's skyline cable deflected sideways against a leave tree (a tree left standing as part of a silviculture plan). The tree momentarily returned upright but then fell seconds later. The worker was struck by the tree and received fatal injuries.

Investigation conclusions

  • Dangerous leave tree fell, striking worker: The skyline and equipment had repeatedly struck a leave tree. The worker then set chokers on felled trees that were underneath other logs. The load was too heavy to be yarded, resulting in the skyline deflecting against the leave tree and causing it to lean over. The leave tree fell seconds later, striking the worker. The significant difference between the load and the yarding system's capacity confirms that the weight of the load was not taken into account while yarding.

Underlying factors

  • Inadequate planning of a forestry operation: There was inadequate planning of the skyline set-up and yarding, resulting in yarding too close to the leave tree. As a result, the skyline struck the leave tree several times. In addition, the logs on top of the pile should have been yarded first.
  • Leave tree not assessed for hazard: A wind event before the day of the incident toppled trees in the same cutblock as the leave tree. In addition, yarding equipment struck the leave tree several times, destabilizing it. This created a dangerous tree that was not assessed or removed to ensure safety.
  • Inadequate supervision: The employer did not effectively supervise the work being carried out, failing to prevent the unsafe yarding of logs. The employer did not ensure the health and safety of the worker.

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Publication Date: May 2014 Asset type: Incident Investigation Report Summary NI number: 2014136050046