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

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

hinge_length_and_thickness
  • 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

notch_diagram
  • 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

open_faced_notch_top
  1. Start Point: Begin at any height.
  2. Angle of Attack: Cut downward at an angle of 70 degrees.
  3. Ending Point: Stop when the cut reaches 1/4 to 1/3 the tree's diameter.

Open-Faced Notch: Bottom Cut (Undercut)

open_faced_notch_bottom
  1. Start Point: Begin at a level that will give at least a 70 degree notch opening. Ideally, you want a 90 degree opening.
  2. Angle of Attack: Cut upward at a 20 degree angle.
  3. Ending Point: Stop when the cut reaches the end point of the face cut.
  4. Don't bypass the end point of your face cut, it will wreck your hinge!

Open-Faced Notch: Back Cut

open_faced_notch_back
  1. Start Point: important Begin on the opposite side of the notch at the same level as the notched corner.
  2. Angle of Attack: Cut flat along a horizontal plane.
  3. 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

open_faced_notch_conventional
  • 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

humbolt_notch
  • 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?