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Chainsaw work and tree felling are more dangerous than fighting fires, policing the worst neighborhoods or even fighting in wars.  The chainsaw is a tool and the potential weapon of your own destruction. Trees are like real big slow bullets that by your own hand and gravity alone will kill or disable you of life. 

The following are case studies from national records to give you an idea of how dangerous this work can be,

Case studies - Fatalities

Terms and practices used in forestry and arboriculture

  • ‘sink cut’ is a triangular cut made near to the base of the trunk in the side of the tree that the tree is intended to fall. It should be made at an angle of approximately 45 degrees.
  • ‘felling cut’ is the horizontal cut made into the rear of the tree, just above and towards the sink cut. The felling cut should stop before it meets the sink cut to create a hinge.
  • The falling action of the tree is controlled because the portion of the tree that has not been cut through creates what is called a ‘hinge’. This allows the felling direction and the rate of the fall to be controlled.
  • ‘Wedges’ are one of the tools used by forestry workers and the use of them to free a jammed chainsaw is not uncommon.
  • ‘bench’ is the term used for the felling one tree into a horizontal position on the ground so that the next tree can be felled to land on top of it. The technique is used to make the task of snedding easier.
  • ‘Snedding’ refers to the removal of branches from the trunk of a felled tree. This is carried out after a tree has been felled and is carried out with a chainsaw.
  • The ‘danger zone’ is an area to the front and rear of a tree, where the tree is most likely to fall either during or after the sink and felling cuts have been made. Appendix 1 (AFAG302 – Basic chainsaw felling and manual takedown) illustrates this at Figure 1.

Working with chainsaws

Falling objects including being struck by a tree

A 67-year old landowner was struck by a tree branch

A 43-year old estate worker was struck by a tree branch.

A 29-year old self-employed firewood supplier was crushed by a fall...

A 37-year-old forester was struck on the head by a falling tree

A 63-year-old man died when a large tree branch hit his head

A 48-year-old man was found trapped beneath a felled tree

An 85-year-old member of the public was crushed by a falling tree b...

A 22-year-old forestry worker was hit by a falling tree during a wi...

A 25-year-old self-employed tree surgeon died after being struck by...

A 61-year-old employee was felling a tree in the back garden of a d...

A 31-year-old employee was struck by a tree during a winching opera...

A 59-year-old, self-employed forestry worker was found late in the ...

A 58-year-old employee was found trapped between two trees.

A 42-year-old self-employed man was killed when he was struck by a ...

A 64-year-old employee was trapped under a section of tree that had...

A 33-year-old employee suffered head injuries when struck by a tree...

A 33-year-old man suffered a broken neck when struck by the trunk o...

31 year old self employed person was hit on the head and became tra...

A 59 year–old, self-employed arborist was killed when a tree sprung...

A 39 year-old, self-employed chainsaw operator was killed when he w...

A 64 year-old self-employed contractor died after being struck on t...

A 39 year-old self-employed contractor was found dead beneath a fel...

A 59 year old arboricultural contractor was struck by a falling tree. 

A 59 year old forestry worker was crushed by a falling tree. 

A 49 year old employee was struck by a falling tree. 

An 18-year-old employee was struck on the head by a tree felled by ...

A 39-year-old self-employed contractor was struck by a tree branch

A 67-year-old self-employed forester was crushed by a falling tree

Lone working

Working at height

Vehicles at work

Contact with an Overhead Power Line (OHPL)

The following key lessons may help save your life.

Initial site survey:
Wherever possible, assess jobs in advance. This allows for correct selection of equipment, allocation of staff and prior knowledge of hazards. It also allows an experienced site surveyor to provide guidance and work methodology to the people carrying out the work.

Risk assessment/emergency planning:
The assessment should take account of the hazards that are relevant and specific to the given site, task and tree. It is not just an exercise on paper; if you cannot control risks to acceptable levels, work on that task must not proceed until suitable arrangements are in place. Emergency contingency plans (first aid, emergency contact numbers, Accident and Emergency number, site location etc) must be made in advance.

Work planning:
All information, as well as the actual undertaking of the job, must be planned, agreed and understood by all the team.

Felling cuts:
Effective control of the fell is maintained by an appropriate combination of the directional or sink cut, hinge and main felling or back cut. Felling cuts must be appropriate to the tree size and form and consistently accurate.

Felling aids (breaker bars, wedges etc):
These must be appropriate to the tree size and form. The need for felling aids must be identified in advance; they must be appropriate and readily available to the person undertaking the fell.

Control lines, pull ropes, anchor ropes, winches etc:
If these types of system are to be used there should be clear understanding of their intended purpose and suitability for the task, eg is it:

  • An assisted fell?
  • An anchor or back up?
  • A felling aid?
  • A winching operation? or
  • A combination of tasks?

Avoid:
‘free hand’ pulling or non-anchored applications. There is a high risk that if the person pulling the rope sways or rocks the tree during the felling operation, the main felling cut at the rear of the tree will open and close with the risk that the chainsaw operator could compromise the integrity of the hinge.

Do not:
over tension lines, as this may place considerable tension on the rear of the tree which may cause the hinge to sever prematurely, the tree to split, and injury to the chainsaw operator.

Avoid:
making the main felling or back cut while your workmate is simultaneously applying tension to the line. As well as the above risks, the chainsaw operator cannot safely place the back cut and monitor the action of his colleague operating the line. In the majority of cases the tree feller should be able to form the back cut, leave a hinge of appropriate size, step into a safe area, and then issue an agreed signal for the person on the lines to start operation.

Escape routes:
Plan escape routes in advance – they must be clear of obstructions. If control is lost over the fell, use the escape route and try not to turn your back on the falling tree. Remember, accidents often happen because unforeseen or remote risks actually materialise. Consider the possibility that the tree may fall towards your intended escape routes. Have you got enough back up to ensure that the tree will fall in the intended direction? Is there enough space to enable you to take evasive action if the unforeseen does occur?

Staff competency and experience:
Staff should have the necessary training, experience and competency certificate relevant to the task they are undertaking. Remember that people holding only CS 30/31 with little additional experience can quickly find themselves in situations outside their experience and skill base. This is particularly true when faced with larger and awkward fells and when faced with the unique hazards associated with arboricultural operations in gardens and the built.

Source:
http://www.hse.gov.uk/treework/resources/chainsaws-tree-felling-kil...

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