Reducing the risks from top-handled chainsaw use
Saw selection and maintenance
Not all top-handled chainsaws are the same. Although the professional range is comparatively small; there are variations in weight, balance and handling characteristics. Select a saw that is appropriate for yourself and the tasks most often carried out. Remember to use appropriate bar, chain and sprocket combinations. These will greatly impact upon cutting efficiency, kickback potential, and overall handling characteristics. Only use those recommended by the manufacturer.
- Maintain the saw as manufacturers guidelines
- Do not use the saw if it is defective in any respect
Planning and preparation
Wherever possible, work should be assessed before hand with a view to determining:
- Is it necessary to climb the tree? Could the work be done from a platform?
- Correct levels of staff, equipment and supervision
- Aerial rescue provisions and emergency contingency plans
Operational: remember, the risks from the saw are not just to the climber. Send the saw aloft using a fail safe system (normally fasten to the harness before removing from haul line) and ensure ground staff are outside of potential drop zones if the saw should fall.
- Is it necessary to use the chainsaw? Could the work be done with a hand saw?
- Establish a secure and stable work position before:
- Hauling the saw into the tree
- Start the saw with the chain break on, away from any obstructions, including climbing ropes and associated equipment
- In most circumstances the saw should be used with two hands
- Assess the timber to be cut, with a view to identifying compression and tension, foreign objects (nails, wire etc) and other parts of the tree which the saw could inadvertently contact and cause kick back
- Consider timber and species characteristics- some trees are brittle or prone to tearing
- Avoid cutting with the tip of the bar
- Plan and be aware of the position of your body and equipment in relation to operation of the saw and a potential 'kickback' arc
- On vertical sections (and generally), maintain saw use below shoulder height. Many operators habitually position the saw (in a potential kick back arc) around shoulder and neck height
- Do not position yourself where loss of work position (slips etc) will result in you falling towards the saw
- Do not lean into the saw whilst cutting or use it to partially brace yourself
- Be aware of the risks of using the saw in hedges or trees with multiple branches / epicormic growth
- If the saw becomes trapped, switch it off before removing
Supervision for the less experienced and trainees
In addition to basic training and certification requirements, trainees and the less experienced must be adequately supervised at all times. It is prudent to have documented systems and procedures in place setting out how this is achieved.
- Tree climbing operations and chainsaw use do not go hand in hand, break the training process into stages over reasonable time frames:
- Competent ground based chainsaw (rear handle!) use
- Consolidation of basic tree climbing skills and establishing sound work positions
- Capable aerial rescue techniques
- Use of handsaw in tree
- Consider using additional PPE in the form of 'chainsaw jackets', etc. to provide extra protection whilst developing top - handled chainsaw skills in the tree.
Aerial rescue provisions
Plan for and put in place effective emergency plans including aerial rescue. There are still too many situations where the most capable climber is aloft, potentially leaving less experienced members, to provide aerial rescue cover with little prospect of recovering their work mate in an emergency.
- Practice and develop aerial rescue skills on a regular basis
- If the climber is approaching a position where the 'rescuer' has any doubts about their ability to provide support in an emergency, pause the work and review.
Whilst nationally recognised training and certification provides the basic foundations for practitioners, it does not confer experience or expertise. This can only be obtained through consolidation of skills in a well controlled and supervised environment. It may take three years before a 'novice' climber is approaching a craftsman like level.
The above points are a brief summation of what I consider to be key factors. I strongly recommend that readers also familiarise themselves with the documents below (in particular the HSE Research Report into Safe working methods with top-handled chainsaws).
- HSE Research Report into Safe working methods with top-handled chainsaws
- AFAG 308 Top-handled chainsaws
The Arboricultural Association's Guide to Good Climbing practice