Landscaping (C-27) · Lesson 7 of 7

Felling Cuts: Notch Depth, Back Cut, and Elevated-Work Rules

"Felling Cuts: Notch Depth, Back Cut, and Elevated-Work Rules" is lesson 7 of 7 in the Landscaping (C-27) Learning Hub. It opens with "A Qualified Tree Worker Runs Every Tree Job" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. A Qualified Tree Worker Runs Every Tree Job
  2. Over 5 Inches: Notch and Back Cut Make the Hinge
  3. The Notch-Depth Math: One-Third of the Diameter
  4. Back-Cut Height and the Escape Route
  5. Working Aloft: Two Means of Support, Second Person, Rated Line

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Is a notch and back cut required?" through "Before the saw starts".

What you'll be able to do

  • Explain the main idea of "Felling Cuts: Notch Depth, Back Cut, and Elevated-Work Rules" in plain language you can use on the exam.
  • Apply this step with confidence: "The Notch-Depth Math: One-Third of the Diameter".
  • Apply this step with confidence: "Back-Cut Height and the Escape Route".
  • Apply this step with confidence: "Working Aloft: Two Means of Support, Second Person, Rated Line".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Felling Cuts: Notch Depth and Back CutSIDE VIEW OF A 24 IN. TRUNKfallnotch depth8 in. maxapexhingeback cut:1 to 2 in.above apexD = 24 in. trunk diameterMAX NOTCH DEPTH = DIAMETER / 3Trunk diameterMax notch depth12 in.4 in.18 in.6 in.24 in.8 in.30 in.10 in.Over 5 in. diameter: notch + back cut (3427(c)(3))Conventional ~45 deg; open-face over 70 deg (3420(b))Conv./Humboldt: back cut 1-2 in. above apexOpen-face: back cut level with apex ((c)(3)(E))Notch cuts must not cross; back cut must notpenetrate the hinge area ((c)(3)(D), (F))Escape route planned first ((c)(2))Audible warning before the fall ((c)(4))Drop zone set before cutting ((b)(2))Aloft above 12 ft: a second employee must be present (3427(b)(9)).Climbing line: 1/2 in. minimum diameter, 5,000 lb minimum tensile strength (3422(c)).24 in. trunk: notch depth at most 24 / 3 = 8 in.Back cut 1 to 2 in. above the apex; cuts do not cross; hinge stays uncutSource: 8 CCR Sec. 3420(b), 3421, 3422(c), 3427(a)-(c) (General Industry Safety Orders, Article 12).CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: A Qualified Tree Worker Runs Every Tree Job

Cal/OSHA's tree-work article (8 CCR Article 12, Sec. 3420-3428) covers work and equipment used in tree and ornamental palm maintenance and removal. Each work location where trimming, repair or removal is done must be under the direction of a qualified tree worker, and that person gives a job briefing before each work assignment covering the hazards, the work procedures and the PPE (8 CCR Sec. 3421(b), (f)). Where two or more employees work at a location, at least two persons trained in first aid and CPR must be available (Sec. 3421(m)). Before felling, the crew considers lean, species and shape, loose limbs, wind force and direction, weak or decayed spots, terrain, nearby hazards and wildlife nests (Sec. 3427(c)(5)).

Step 2: Over 5 Inches: Notch and Back Cut Make the Hinge

A notch and back cut must be used to establish a hinge when felling trees over 5 inches in diameter (8 CCR Sec. 3427(c)(3)). The hinge is the strip of uncut wood fibers between the notch and the back cut that steers the fall (Sec. 3420(b)). The notch may be a conventional notch (face cut plus an angle cut above it, about 45 degrees), a Humboldt notch (angle cut below the face cut, about 45 degrees, usually for large trees on steep slopes), or an open-faced notch (two cuts making an angle greater than 70 degrees) (Sec. 3420(b); Sec. 3427(c)(3)(B)).

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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