MIS315 Chainsaw Operation and Tree Felling

This book is one in a series of Minimum Industry Standards produced by Arboriculture Australia Ltd and the New Zealand Arboricultural Association in consultation with the national arboriculture community in both countries. These industry peer-reviewed documents provide a ‘body of knowledge’ which is shared by practitioners and can be used as the basis for training, dissemination of skills and professional development.

This standard covers the work tasks of preparing, maintaining and using chainsaws, as well as tree felling using a variety of cuts and techniques both from the ground and whilst working at height.

Contents:

A Minimum Industry Standard for chainsaw use and tree felling
Industry partners
How to use this Minimum Industry Standard

• Other applicable Minimum Industry Standards

1: Introduction to chainsaws

Chainsaw components and terminology

• Powerhead
• Cutting attachment
• Drive sprocket
• Guide bar
• Saw chain
• Battery saws
• Top-handled saws

2: Chainsaw maintenance

• Pre-start checks and routine maintenance
• Mixing fuel
• Common fuel:oil mixtures
• Periodic maintenance
• Sharpening saw chain
• File size and depth gauge chart
• Work position for sharpening
• Sharpening sequence

3: Chainsaw operation

Chainsaw safety: general principles

• General principles of safe work and risk management
• Personal Protective Equipment for chainsaw use

Working with chainsaws

• Starting the chainsaw
• Drop starting
• Starting a top-handled saw
• Starting a saw in a MEWP
• Using a chainsaw
• Basic operation principles
• Operating the chain brake
• Work positions for chainsaw operation
• Chainsaw reaction forces
• Kickback
• Good saw control
• Bad saw control
• Shortcuts and bad habits
• Boring cuts

Trimming and crosscutting

• Internal stress in branches and timber
• General safety principles for trimming and crosscutting
• Trimming patterns
• Crosscutting
• Cut sequences for crosscutting
• Processing uprooted trees

4: Tree felling

General principles of directional felling

• Standard directional felling cuts
• How directional felling cuts work
• The function of hingewood
• Compromised hingewood
• Trees with side lean
• Scarf types and features
• Anatomy of a standard scarf
• Humboldt scarf
• Open-face scarf
• 90° scarf
• Back cut
• Anatomy of a back cut
• Incorrect cuts and felling risks
• Scarf cut too deep
• Scarf cuts not matching (undercutting)
• Scarf cuts not matching (scarf line incorrect)
• Back cut too low
• Back cut overcut (cut through hinge)
• Barber’s chair

Standard tree felling procedure

1. Identify potential fall zone(s)

• Estimating furthest point of impact
• Additional considerations for furthest point of impact
• Estimating area of fall zone
• Margin of error
• Preparing the fall zone for tree felling

2. Determine if it is possible to fell the tree into the fall zone

• Natural lean of tree
• Hinge control
• Tree-specific hazards
• Crew ability
• Reasonable worst case

3. Confirm plan with crew and assign work roles

4. Prepare for felling

1. Clean around base of tree
2. Prepare escape routes
3. Set pulling ropes or guy ropes
4. Prepare other equipment

5. Perform felling operation

• Cut the scarf
• Work position for scarf cutting
• Hand position for scarf cutting
• Using the gunning sights
• Scarf cuts on larger diameter trees
• Wing cuts

• Make the back cut
• Planning the back cut
• Back cut method 1: straight cut
• Back cut method 2: bore cut
• Back cut method 3: safe corner method

• Use wedges or pulling ropes
• Use escape routes
• Check for hazards before returning to stump

Additional felling techniques

Wedges

• How wedges work
• Wedge selection
• Using wedges

Small trees

• Wedge bore method
• Quarter cut / split-level cut

Large trees

• Centre scarf method

Standing timber

• Cut techniques for standing timber

Forward-leaning trees

• Back-release cut (strap cut)

Backward-leaning trees

Trees with a sideways lean

• Tapered hinge and wedge

Trees with compromised timber

• Compromised hingewood

• Cavities and burnt-out trees

Trees with multiple leaders

Pulling ropes

• General principles for use of pull ropes in felling
• Leverage
• Angle of pull
• Direction of pull
• Pulling against a side lean
• Method of pull
• Key safety points for pulling trees
• Felling sequence when using pulling ropes
• 1: Install the pulling rope (throwing knot)
• Moving the pulling rope into a union
• Using a throwline
• Manipulating a throwline
• Setting the rope with the throwline
• Tying off the rope
• 2: Pre-tensioning the rope
• 3: Cut the scarf and back cut
• 4: Drive wedges in the back cut
• 5: The feller should leave the base of the tree
• 6: The tree is pulled over
• Pulling heavily-leaning trees
• Limiting factors for tree pulling
• Guying trees for felling
• Planning to guy a tree during felling
• Key points for felling guyed trees
• Side-stepped cuts
• Machine-assisted felling
• Stepped-down back cuts

5: Chainsaw use at height

• Tree access methods
• General principles for chainsaw use at height
• Work positioning
• Bad working positions
• Good working positions
• Attachment points when climbing and cutting
• Off-handed and one-handed saw use
• Off-handed use of rear-handled saws
• One-handed use of top-handled saws

Cut sequences and techniques – branches

• Straight back cut
• Step cut – undercut made first – top cut inside
• Step cut – undercut made first – top cut outside
• Step cut – top cut made first
• Step cut – vertical cuts
• Scarf and back cut – downward
• Scarf and back cut – upward
• Box cut
• Scarf and back cut – directional hinge

Cut sequences and techniques – tree heads and timber

• Felling the head out of a tree
• Felling sections of timber
• Felling sections of timber – landing sections flat
• Cutting techniques where trunk diameter is greater than bar length
• Blocking down: step cuts on timber
• Felling techniques for tree dismantling – use of wedges and pulling ropes

Glossary

Notes and References

Minimum Industry Standards

• Using the MIS in training and assessment
• Disclaimer for Minimum Industry Standards and all associated documents
• Industry stewardship program