MIS315 – Chainsaw Operation and Tree Felling (Member Price)

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

• Clean around base of tree

• Prepare escape routes

• Set pulling ropes or guy ropes

• Prepare other equipment

5. Perform felling operation

5.1. 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

5.2. 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

5.3. Use wedges or pulling ropes

5.4. Use escape routes

5.5. 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