Logging Safety: A Field Guide
Section Three: Manual Felling
The Cold Hard Facts
- More loggers are hurt and killed during felling than any other activity!
- Most who die at work are killed within 10 feet of the stump.
- These accidents can be avoided!
To Safely Fell Any Tree You Should....
- Use proper personal protective equipment (PPE).
- Identify potential hazards and ways to avoid or eliminate hazards.
- Determine the best felling direction.
- Plan, clear and use an escape path.
- Figure out the proper hinge size.
- Perform the correct cut.
- Use proper controlled felling by making the correct cuts.
Potential Felling Hazards and Ways to Eliminate or Avoid Them
| Potential Hazard | Description | Ways to Eliminate or Avoid |
|---|---|---|
| Throwback | As the tree falls through other trees or lands on objects, those objects or branches may get thrown back toward the logger. | If possible, avoid felling into other trees or onto objects. |
| Dangerous Terrain | If the tree falls onto stumps, rocks, or uneven ground, a hazard may be created. | If possible, move the obstacle or change the felling direction. |
| Lodged Tree, (Hang) | A tree that has not fallen completely to the ground because it is lodged or leaning against another tree. | Do not work around lodged trees. Push or pull down these death traps using a machine. Never cut the support tree. |
| Widowmakers | Broken-off limbs that are hanging freely in the tree to be felled or in trees close by. | Knock them down or pull them down with a machine. Avoid working underneath them. |
| Snag | Standing dead tree, standing broken tree, or a standing rotted tree to be felled or nearby. | Use a machine to bring it down or it must be felled or avoided by at least two tree lengths. |
| Spring Pole | A tree, segment of a tree, limb or sapling which is under stress or tension due to the pressure or weight of another tree or object. | Use a machine to release the tension or release it with a chain saw by shaving wood from the underside (see limbing and bucking section). |
| Extreme Weather | Strong winds, hazardous snow or ice conditions, electrical storms, dense fogs, fires, landslides and darkness. | Do not fell trees during these extreme weather conditions as they may impair vision and create serious hazards. Terminate work and move to safety. |
| Other Workers and Machines | Workers or machines in the immediate area. Request the workers or machines be removed. | Potential Hazard Description Ways to Eliminate or Avoid |
Plan Your Felling Direction
Planning helps prevent damage to the trees and harm to you!
- Clear a fall path and landing zone.
- Think about the lean of the tree.
- Think about the slope of the ground.
Escape Path: A Safe Retreat
- Plan escape route at 45 degree angles from the sides and back on either side.
- Never move behind the tree to be felled!
- Never assume that you can predict what a tree will do!
- Expect the unexpected.
Use an Escape Path: How to Retreat
- Use the chain brake!
- Use a bore cut and a release cut to give you enough time to retreat.
- Don't turn your back on a falling tree.
- Quickly walk at least 20 feet away.
- Try to position yourself behind a standing tree, if possible.
Why a Felling Hinge?
- It provides controlled directional felling.
- It holds the tree to the stump during most of the tree's fall.
- It guides the tree in the intended direction.
- It makes things more predictable!
A Proper Hinge
- The length of the hinge should be 80% of the diameter of the tree.
- Example: For a 20 inch diameter tree, the hinge should be 16 inches long.
- 20 inches x 80% (0.8) = 16 inches.
- The thickness of the hinge should be 10% of the diameter of the tree.
- Example: For a 20 inch diameter tree, the hinge should be 2 inches wide.
- 20 inches x 10% (0.1) = 2 inches.
Making the Cuts
The felling of a tree includes making three precise cuts (top cut, bottom cut and back cut) to create one of the following three notches:
- Open-faced notch safest
- Conventional notch less safe
- Humbolt notch least safe
Open-faced Notch - SAFEST
- Hinge closes just before tree hits the ground.
- Provides a higher degree of safety and accuracy.
- Less chance of kick back and out-of-control movement.
Open-Faced Notch: Top Cut
- Start Point: Begin at any height.
- Angle of Attack: Cut downward at an angle of 70 degrees.
- Ending Point: Stop when the cut reaches 1/4 to 1/3 the tree's diameter.
Open-Faced Notch: Bottom Cut (Undercut)
- Start Point: Begin at a level that will give at least a 70 degree notch opening. Ideally, you want a 90 degree opening.
- Angle of Attack: Cut upward at a 20 degree angle.
- Ending Point: Stop when the cut reaches the end point of the face cut.
- Don't bypass the end point of your face cut, it will wreck your hinge!
Open-Faced Notch: Back Cut
- Start Point: important Begin on the opposite side of the notch at the same level as the notched corner.
- Angle of Attack: Cut flat along a horizontal plane.
- Ending Point: very important Stop at a point that will leave a hinge width 1/10 of the tree's diameter.
Conventional Notch - LESS SAFE
- Hinge closes in the middle of the fall.
- Lesser degree of safety.
- Less accuracy.
- More chance of kick back.
- Hinge breaks early.
Humbolt Notch - LEAST SAFE
- Hinge closes in the middle of the fall.
- Lesser degree of safety.
- Less accuracy.
- More chance of kick back.
- Saves a little wood; is NOT worth the risk.
Safe Felling Checklist
- Are you wearing all of your PPE (hard hat, chaps, eye and face protection, hand and foot protection)?
- Is your work zone free from danger trees, hangs, snags, and dead limbs?
- Did you look over the position, condition, and lean of the tree?
- Is the situation hazardous or unfamiliar?
- If so, did you talk to your supervisor about it?
- Do you have a clear fall path and landing zone?
- Have you planned and cleared an escape path?
- Do you plan on using controlled directional felling?
- Will the technique include a notch and back cut that leaves a sufficient hinge?
- Are you at least two tree lengths from other workers and machines?
