eTool : Logging - Manual Operations - Felling Trees - Making the Cuts - Kinds of Notches | OSHA.gov | Occupational Safety and Health Administration

	Open-faced Notch Click here to learn how to cut an Open-faced Notch	Conventional Notch Click here to learn how to cut a Conventional Notch	Humbolt Notch Click here to learn how to cut a Humbolt Notch
Total angle	ideally 90 degrees; at least 70 degrees	45 degrees	45 degrees
Top Cut	angled downward 70 degrees	angled downward 45 degrees	flat horizontal
Bottom Cut	angled upward 20 degrees	flat horizontal	angled upward 45 degrees
Back Cut	horizontal; at the same height as the corner of the notch	horizontal; at least 1 inch above the bottom cut	horizontal; at least 1 inch above the top cut
Depth	1/4 - 1/3 of tree diameter	1/4 - 1/3 of tree diameter	1/4 - 1/3 of tree diameter
Point of notch closure	just before tree hits ground	middle of fall	middle of fall
Degree of safety	high	medium	medium
Advantages	greater accuracy of felling into target area hinge stays intact until tree hits ground less danger of kickback and other out-of-control movement	familiar to many loggers	saves slightly more wood familiar to many loggers
Disadvantages	hinge may have to be cut off	hinge breaks early	hinge breaks early