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Subchapter 7. General Industry Safety Orders
Group 3. General Plant Equipment and Special Operations
Article 12. Tree Work, Maintenance or Removal
(a) Scope. This standard applies to work performed and equipment used in tree and ornamental palm maintenance and removal.
NOTE 1: Requirements for fall protection in date palm operations and for ladders attached to date palms are provided in the General Industry Safety Orders, Sections 3458 and 3458.1.
NOTE 2: For line clearance tree trimming operations in proximity to high voltage energized conductors, refer to the provisions of Article 38 of the High-Voltage Electrical Safety Orders, Title 8, California Code of Regulations.
Apex. The point at which two saw cuts meet to form a notch.
Back Cut. The cut made in the tree limb or trunk on the side opposite the intended direction of fall.
Brush Chipper. Equipment used to reduce tree debris to wood chips.
Bucking. The process of cutting the downed tree into appropriate lengths.
Climbing Hitch. A hitch used for securing a tree climber to the climbing line, permitting controlled ascent, descent, and work positioning.
Climbing Lines (Climbing Ropes). Rope that is designed by the manufacturer to support the climber while aloft in a tree.
Climbing Spurs. Sharp devices strapped to a climber's lower legs to assist in climbing trees.
Come-along. A portable, hand-operated winching device, using cable or ropes to draw two objects closer together.
Crotch. Branch union; the angle formed by two branches in the tree.
Double-crotching. A climbing method that uses the rope's opposite end or a second rope to enhance stability.
Drop starting. The act of starting a power saw by simultaneously pushing the saw away from the body with one hand while pulling on the starter cord handle with the other.
Drop Zone. The area established by a qualified tree worker beneath employees aloft involved in tree work operations and/or where the potential exists for struck-by injuries from objects dropped or lowered from above.
Felling. Cutting down an entire tree or standing section of a tree in one piece, from the ground, by incorporation of a notch and back cut.
Frond. A large compound leaf of a palm.
False Crotch. A system, other than a natural crotch, used to support a climbing line.
Hinge. A strip of uncut wood fibers created between the face cut or notch and the back cut that helps control direction in tree felling or limb removal.
Leader. The stem or trunk of a tree usually growing in the upright position.
Lightning Protection System. Hardware installed in a tree intended to reduce the risk of damage from a lightning strike.
Limbing. The removal of branches from either standing or downed trees.
Notch. A wedge cut into the tree or tree section facing the intended direction of fall to control the felling direction.
(A) Conventional Notch. A directional felling cut into the side of a tree, facing the intended direction of fall and consisting of a horizontal face cut and an angle cut above it, creating a notch of approximately 45 degrees.
(B) Humboldt Notch. A directional felling cut into the side of a tree, facing the intended direction of fall and consisting of a horizontal face cut and an angled cut below it, creating a notch of approximately 45 degrees. A Humboldt notch is usually reserved for larger trees on steep slopes.
(C) Open-faced Notch. A directional felling cut into the side of the tree facing the intended direction of fall and consisting of two cuts creating a notch greater than 70 degrees.
Ornamental Palm. A palm that is primarily for landscaping or scenery and not grown for the production and harvesting of fruits, such as dates for personal use or sale.
Palm Frond Skirt. One or more year's accumulation of dead and drooping palm fronds at the bottom of the palm's canopy and along its trunk.
Proximity. An area within 10 feet (3.05 meters) of energized overhead electrical conductors rated 50 kilovolts (kV) phase to phase or less. For overhead electrical conductors rated more that 50 kV phase to phase, the distance is increased 4/10 inch (10 millimeters) for each additional kV.
Prusik Loop. An endless loop of rope used to fashion the Prusik knot (which is a sliding friction knot). The endless loop may be spliced or knotted with, at minimum, a double fisherman's knot.
Qualified Tree Worker. An employee who, through related training and on-the-job experience, has demonstrated familiarity with the techniques and hazards of tree maintenance, removal, and the equipment used in the specific operations involved.
Root Collar. A flared area at the tree trunk base where the roots and trunk come together.
Rope(s). Includes climbing lines and climbing ropes unless otherwise stated, and includes all other ropes and lines used in tree work, maintenance and removal operations.
Secured (person). A tree worker that is safeguarded by utilizing a climbing system attached to the tree worker and connected to a tree or other stable support.
Split Tail. A short section of climbing line with one end connected by a self-closing, self-locking carabiner or snap hook to the suspension D-rings of the tree saddle and the opposite end connected to the climbing line by a climbing hitch.
Step Potential. The voltage difference between the feet of a person standing near an energized grounded object. It is equal to the difference in voltage, given by the voltage distribution curve, between two points at different distances from the electrode.
Structural Support System. Consists of cabling between branches, installation of rods or bracing or other hardware used to keep the tree or its limbs structurally solid.
Tied In. When a tree worker's climbing line has been run through a natural or false crotch attached to the tree worker's saddle and completed with a climbing hitch or mechanical device, permitting controlled movement and work positioning.
Tree Climbing System. A collection of equipment used together for work positioning in a tree and generally consisting of a tree worker's saddle, one or more climbing lines, one or more work positioning lanyards and associated hardware.
Tree Worker's Saddle. An arrangement of straps, fittings, and buckles or other elements in the form of a waist belt with a low attachment element or elements and connecting support encircling the legs, suitably arranged to support the body in a sitting position.
Work-positioning Lanyard. For purposes of Article 12, a component of a tree climbing system consisting of a short section of approved rope, strap or line that has a rope snap or carabiner at either end, and that is used as a point of attachment to the tree or ornamental palm for securing the worker in the tree while aloft.
1. New article 12 (sections 3415-3418, not consecutive) filed 11-12-75; effective thirtieth day thereafter (Register 75, No. 46).
2. Repealer of article 12 (sections 3415-3418, not consecutive) and new article 12 (sections 3420-3428 and Appendix A) filed 4-16-80; effective thirtieth day thereafter (Register 80, No. 16). For prior history, see Register 76, No. 21.