Increasing the use of grapple extraction on steep slopes (FFR)


  • Harvesting costs on steep slopes have continued to increase
  • The proportion of harvest on steep slopes will increase as the harvest from ‘non-corporate’ forests increases.
  • Conventional harvesting practices with manual felling and breaking out are physically demanding and hazardous with 3-4 fatalities on average each year and many serious lost time injury accidents.
  • High productivity cable systems such as grapple extraction have not been widely adopted by contractors in NZ.

Potential benefits

Removal of people from hazardous operations in felling and breaking out.

Reduction in the total number of people engaged in steep slope harvesting with increase in labour productivity.

People engaged in safer more attractive and less physically demanding/hazardous activities such as machine operators. Breaking-out accidents are eliminated.

Improving productivity of steep slope harvesting to achieve a 25% reduction ($8 per tonne) in harvesting costs – worth an estimated $55m by 2016 and rising to $85m by 2020.


Improving vision for grapple operator through development of strategically located remote controlled video cameras.

Evaluation and development of improved grapple control systems including grapple restraints and carriages.


A commercially robust camera system has been developed for a grapple that has been successfully tested. To date, 2 units have been sold to external contractors and feedback is that operators are achieving reduced cycle times and greater grapple payloads.

A cutover camera system has been tested and is currently undergoing field tests in a swing yarder. Operator feedback is positive.

A low-cost grapple constraint device has been developed by Scion that has resulted in a 4.5% improvement in productivity and a 2 month payback on an investment of $1500.

A lightweight hydraulic grapple carriage is under evaluation.


The PGP Harvesting programme has resulted in a renewed focus on innovation in harvesting.

Early programme outcomes are being applied and are resulting in productivity improvements that are needed to reduce steep slope harvesting costs and improve the safety and attractiveness of harvesting work.

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