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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
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§3427. Safe Work Procedures.

(a) Climbing and Access.

(1) Prior to climbing the tree, the employer shall ensure that the tree, including the root collar, is visually inspected by a qualified tree worker who shall determine and ensure a safe method of entry into the tree. The location of all electrical conductors and equipment within the work area shall be identified in relation to the work being performed. Climbing lines, ropes, lanyards, and other climbing equipment shall be inspected in accordance with the provisions of Section 3422(j) of this Article 12.

(A) Only when a tree cannot be safely accessed by climbing or the use of aerial devices, a qualified tree worker may be hoisted into position by using an approved tree worker's saddle secured to a crane's hook that shall be closed with a positive locking device. The tree worker's saddle shall also be secured to an independent line attached above the crane hook, and the following criteria shall be met:

1. All climbing equipment, lines and rigging shall have a minimum breaking strength of at least 5,000 pounds.

2. The crane boom and load line shall be moved in a slow, controlled, cautious manner with no sudden movements when the qualified tree worker is attached to the crane.

3. The requirements for hoisting employees by crane in a personnel platform contained in Sections 5004(d)(2), (4), (5), (6), and 5004(e) shall apply to the hoisting of a qualified tree worker suspended in an approved tree worker saddle.

4. Cranes used for tree work shall be equipped with a functional load indicating device.

5. The crane operator shall be familiar with the potential hazards and operational techniques encountered in tree work.

6. The qualified tree worker being hoisted shall be in continuous communication with the crane operator, or signals shall be relayed by a qualified signal person as provided in Section 5001.

7. The crane operator shall remain at the controls when the qualified tree worker is attached to the crane.

8. The qualified tree worker shall be detached from the crane while the load is hoisted.

9. The employer shall ensure that the crane operator and qualified tree worker determine the weight of the load being lifted to prevent the crane from being overloaded.

10. The hoisting of a qualified tree worker shall be promptly discontinued upon indication of any dangerous weather conditions or other impending danger.

NOTE: 1. Other applicable provisions pertaining to crane operations are contained in the General Industry Safety Orders, Group 13, Cranes and Other Hoisting Equipment.

NOTE: 2. For line clearance tree trimming operations, see Article 38 of the High Voltage Electrical Safety Orders.

(B) Special Training Requirements. The employer shall ensure that every qualified tree worker involved in tree work utilizing a crane to position personnel into a tree under the provisions of Section 3427(a)(1)(A), receives instruction and training on such work and is competent in the following areas:

1. Safe work procedures and knowledge of the hazards applicable to tree work involving the use of cranes.

2. The use of personal protective equipment required for tree work.

3. The inspection and safe use of all climbing equipment, lines and rigging.

4. Crane signals and communication requirements with the crane operator as provided in Section 5001.

5. Instructions regarding electrical hazards as described in Section 3423.

6. The safe use of chain saws in tree work.

7. The conditions and criteria necessary to permit the use of a crane to provide access into a tree.

8. The handling of loads as described in Section 4999 and rigging techniques for tree work.

9. Effective means for controlling pedestrian and vehicular traffic.

(C) Documentation of employee training required by Section 3427(a)(1)(B) shall be maintained as prescribed by Section 3203 of these Orders.

(2) When working aloft, employees shall wear a tree workers' saddle and have at least two means of being secured, such as a climbing line and a work positioning lanyard.

(3)(A) Employees shall be tied in or secured while ascending the tree and remain tied in or secured until the work is completed and they have returned to the ground.

(B) Employees shall not work from or leave a ladder to gain access to a tree unless the employee is tied in or otherwise secured to the tree.

EXCEPTION: Employees may work from a self-supporting ladder in accordance with the manufacturer's instructions.

(4) The tie-in point shall be established on or around the main leader or a major upright branch of the tree as high as necessary using branches with a wide crotch to prevent any binding of the climbing line. The crotch selected for tying-in shall be over the work area as nearly as possible, but located in such a way that a slip or fall would not permit the employee to come in contact with any electrical conductor, equipment or other hazard.

(b) Pruning, Trimming and Tree Removal Operations.

(1) The employer shall establish a method of verbal or visual communication which shall be reviewed during the job briefing, prior to the start of pruning or removal operations. The verbal or visual communication system shall use an established command and response system or pre-arranged, two-way hand signals. The communication method shall be clearly understood and used during all rigging operations. The command “stand clear” from aloft and the response “all clear” from the ground are some terms that may be used for verbal communication.

(2) A drop zone shall be established prior to the start of pruning or removal operations. Employees not directly involved in the pruning or removal operation shall stay out of the pre-established drop zone until it has been communicated by a qualified tree worker directly involved in the operation that it is safe to enter the drop zone. Employees shall be positioned and their duties organized so that the actions of one employee will not create a hazard for any other worker.

(3) Only qualified tree workers directly involved in the operation shall be permitted in the drop zone when a load is being suspended by a rigging system.

(4) When a rigging system is necessary, a qualified tree worker shall determine the appropriate rigging system for the removal project based on factors that include, but are not limited to, the species, size, weight, and length of tree sections or limbs being removed.

(5) When it is necessary to remove branches or sections of a tree that will be removed, a qualified tree worker who is trained and experienced in rigging operations shall determine whether the tree can withstand the strain of the lowering procedures. If the determination is that the tree cannot do so, other means of removing the tree shall be considered.

(6) Wedges, block and tackle, rope, and other lowering devices shall be used when there is a danger that a tree or trees being removed may fall in the wrong direction or damage property. All limbs and sections shall be removed to a height and width sufficient to allow the tree to fall clear of any wires or other objects in the vicinity.

(7) Separate ropes for lowering limbs shall be attached to limbs which cannot be dropped or are too heavy to be controlled by hand. Climbing lines shall not be attached to the same crotch as ropes used for lowering limbs.

(8) Cut branches (hangers) shall be removed from the tree prior to leaving the job site.

(9) When an employee is elevated above 12 feet in any tree work operations including climbing ladders, climbing into the tree or using an aerial device, a second employee shall be present to render immediate assistance.

(10) Palm frond skirts shall be removed from the top down. Qualified tree workers performing this work shall be supported by a climbing line and a false crotch attached above the frond skirt, or they shall work from an aerial device.

EXCEPTION: Fronds may be trimmed from below the dead frond accumulation only when a qualified tree worker who is competent and experienced in palm tree work and the hazards associated with removing dead fronds makes a determination that this task can be safely performed from below.

NOTE: Because palm frond skirts have the potential of unexpectedly releasing onto a worker below, the ANSI Z133.1-2006 standard “Arboricultural Operations - Safety Requirements” Section 8.2.7 states that tree workers shall never attempt to remove palm frond skirts of three years or more growth by positioning themselves below the work areas while being supported by a lanyard.

(11) When dry conditions exist, no employee shall smoke in or near dead palm fronds. All chain saws used under such conditions shall have mufflers and spark arresters in good working condition.

(c) Felling.

(1) The work area shall be cleared to permit safe working conditions before any cutting is started.

(2) A planned escape route for all workers shall be prepared before cutting any standing tree or trunk.

(3) A notch and back cut shall be used to establish a hinge when felling trees over 5 inches in diameter.

(A) Notches and back cuts shall be made at a height that enables the chain-saw operator to safely begin the cut, control the tree or trunk, and have freedom of movement for escape.

(B) The notch cut used shall be a conventional notch, an open-faced notch, or a Humboldt notch as defined in Section 3420(b).

(C) The notch depth shall not exceed one-third of the diameter of the tree.

(D) The back cut shall not penetrate into the predetermined hinge area.

(E) With a conventional notch or Humboldt notch, the back cut shall be 1 to 2 inches above the apex of the notch to provide an adequate platform to prevent kick-back of the tree or trunk. With an open-face notch (greater than 70 degrees), the back cut shall be at the same level as the apex of the notch.

(F) The two saw cuts that form a notch shall not cross at the point where they meet.

(4) Just before the tree or trunk is ready to fall, an audible warning shall be given to those in the area. Pre-arranged, two-way hand signals may also be used as a warning, provided that only qualified persons shall give such signals. All non-involved personnel in the vicinity shall be safely out of range before the tree or trunk falls.

(5) Prior to the start of any tree felling or removal operations, the hazards and relevant factors pertaining to the tree and the site are to be considered by undertaking actions that include, but are not limited to, the following:

(A) Identifying potential hazards in the area surrounding the tree to be removed, including nearby trees.

(B) Determining the species and shape of the tree.

(C) Evaluating the lean of the tree.

(D) Inspecting for loose limbs and wood chunks, or other overhead material.

(E) Evaluating the wind force and direction.

(F) Identifying decayed or weak spots in the tree.

(G) Providing a means to protect other persons, property, and electrical conductors.

(H) Evaluating the terrain characteristics and/or limitations of the work area; and

(I) Identifying evidence of bees or other wildlife habitation in the tree that may present hazards.

(d) Bucking.

(1) The employee shall work from the uphill side whenever possible during limbing or bucking operations.

(2) The employee shall block the log during bucking operations to prevent rolling, when necessary.

(3) When bucking trunks of trees, wedges shall be used when necessary to prevent binding the chain saw guide bar or chain.

(e) Structural Support Systems, and Lightning Protection Systems.

(1) Employees on the ground shall not stand in the drop zone during the installation of structural support systems or lightning protection systems.

(2) Tools used to install structural support systems or lightning protection systems shall be carried in a bag or on a belt designed to hold such tools or attached to a tool lanyard.

(3) Employees installing cabling, support systems or lightning protection systems shall be positioned off to one side in order to avoid injury in case of a cable system failure that could occur when a block and tackle or hand winch is released.

(4) When removing a cable from a tree, a block and tackle or come-along system shall be used before removing the cable.

(5) When installing a replacement cable, the replacement cable shall be fully installed before removing the outdated cable.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. Amendment filed 8-8-85; effective thirtieth day thereafter (Register 85, No. 32).

2. Amendment of subsections (a)-(a)(1), new subsection (a)(2) and subsection renumbering filed 4-1-2004; operative 4-1-2004 pursuant to Government Code section 11343.4(c) (Register 2004, No. 14).

3. Amendment of subsection (a)(1), new subsections (a)(1)(A)-(a)(1)(A)8., repealer of former subsection (a)(2) and subsection renumbering filed 4-29-2004 as an emergency; operative 4-29-2004 (Register 2004, No. 18). A Certificate of Compliance must be transmitted to OAL by 8-27-2004 or emergency language will be repealed by operation of law on the following day.

4. Amendment of subsection (a)(1), new subsections (a)(1)(A)-(a)(1)(A)8., repealer of former subsection (a)(2) and subsection renumbering refiled 8-26-2004 as an emergency; operative 8-26-2004 (Register 2004, No. 35). A Certificate of Compliance must be transmitted to OAL by 12-24-2004 or emergency language will be repealed by operation of law on the following day.

5. Certificate of Compliance as to 8-26-2004 order, including further amendment of subsections (a)(1)-(a)(1)(A)1., new subsections (a)(1)(A)4.-5., subsection renumbering and new subsections (a)(1)(B)-(C), transmitted to OAL 12-17-2004 and filed 1-24-2005 (Register 2005, No. 4).

6. Amendment filed 9-25-2012; operative 10-25-2012 (Register 2012, No. 39).

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