36C78618Q0261-010.pdf

ANSI A300 (Part 1)-2001 Pruning Revision of ANSI A300-1995

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American National Standard for Tree Care Operations –

ANSI

A300 (Part 1)-2001

Revision of

ANSI A300-1995

Approved May 22, 2001

American National Standards Institute, Inc.

Headquarters:

1819 L Street, NW Sixth Floor Washington, DC 20036

New York Office:

25 West 43rd Street Fourth Floor New York, NY 10036

Secretariat

National Arborist Association, Inc.

Tree, Shrub, and Other Woody Plant Maintenance – Standard Practices (Pruning)

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Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the stan-dards developer.

Consensus is established when, in the judgement of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests.

Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made towards their resolution.

The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards.

The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpre-tations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard.

CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute.

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National Arborist Association, Inc., 3 Perimeter Rd. Unit 1, Manchester, NH 03103 Phone: (800) 733-2622 or (603) 314-5380 Fax: (603) 314-5386 E-mail: naa@natlarb.com www.natlarb.com

Copyright © 2001 by the National Arborist Association All rights reserved.

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C o n t e n t s Page

Foreword ..................................................................................................................................................... ii

1 ANSI A300 Standards – Scope, purpose, and application

2 Part 1 – Pruning Standards

3 Normative References

4 Definit ions

5 Pruning Practices

Figures

5 . 3 . 2 A pruning cut that removes a branch

5 . 3 . 3 A pruning cut that reduces the length of a branch or stem

5 . 3 . 7 A final cut that removes a branch with a narrow angle of attachment

Annex

A Reference publications i

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(This foreword is not part of American National Standard A300 Part 1-2001.)

An industry-consensus standard must have the input of the industry that it is intended to affect. The Accredited Standards Committee A300 was approved June 28, 1991. The committee includes representatives from the residential and commercial tree care indus-try, the utility, municipal, and federal sectors, the landscape and nursery industries, and other interested organizations. Representatives from varied geographic areas with broad knowledge and technical expertise contributed.

The A300 standard can be best placed in proper context if one reads its Scope , Purpose, and Application. This document presents performance standards for the care and mainte-nance of trees, shrubs, and other woody plants. It is intended as a guide in the drafting of maintenance specifications for federal, state, municipal, and private authorities including property owners, property managers, and utilities.

The A300 standard stipulates that specifications for tree work should be written and ad-ministered by a professional possessing the technical competence to provide for, or su-pervise, the management of woody landscape plants. Users of this standard must first interpret its wording, then apply their knowledge of growth habits of certain plant species in a given environment. In this manner, the user ultimately develops their own specifications for plant maintenance.

ANSI A300 Part 1 – Pruning, should be used in conjunction with the rest of the A300 standard when writing specifications for tree care operations.

Suggestions for improvement of this standard should be forwarded to: NAA300 Secretary, c/o National Arborist Association, 3 Perimeter Rd. - Unit 1, Manchester, NH 03103, USA or Email: naa@natlarb.com.

This standard was processed and approved for submittal to ANSI by Accredited Stan-dards Committee on Tree, Shrub, and Other Woody Plant Maintenance Operations – Standard Practices, A300. Committee approval of the standard does not necessarily imply that all committee members voted for its approval. At the time it approved this standard, the A300 committee had the following members:

F o r w a r d

American Forests .............................................................................................................Staff (Observer) American Nursery and Landscape Association .............................................. Craig J. Regelbrugge American Society of Consulting Arborists ................................................................. Andrew Graham

Donald Blair (Adviser) Beth Palys (Adviser)

American Society of Landscape Architects .................................................................... Ron Leighton Asplundh Tree Expert Company ..................................................................................... Geoff Kempter Associated Landscape Contractors of America ...................................................... Preston Leyshon

Jeff Bourne (Alt.)

The Davey Tree Expert Company .............................................................................. Joseph Tommasi

Dick Jones (Alt.)

Richard Rathjens (Adviser)

The F.A. Bartlett Tree Expert Company .............................................................................Peter Becker Dr. Thomas Smiley (Alt.)

International Society of Arboriculture ................................................................................. Ed Brennan Sharon Lilly (Alt.)

National Arborist Association ............................................................................................Ronald Rubin Tom Mugridge (Alt.)

National Park Service........................................................................................................ Robert DeFeo Professional Grounds Management Society ............................................................ Kevin O’Donnell Society of Municipal Arborists ....................................................................................... Andrew Hillman U.S. Forest Service ..................................................................................................................... Ed Macie

Mike Galvin (Alt.)

Philip D. Rodbell (Alt.)

Tim Johnson, Chair (Artistic Arborist, Inc.)

Bob Rouse, Secretary (National Arborist Association, Inc.)

Organizations Represented Name of Representative i i

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Organizations Represented Name of Representative Utility Arborist Association ...................................................................................................Jeffery Smith

Matt Simons (Alt.)

i i i

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1 ANSI A300 standards

1 . 1 S c o p e

ANSI A300 standards present performance standards for the care and maintenance of trees, shrubs, and other woody plants.

1 . 2 P u r p o s e

ANSI A300 standards are intended as guides for fed-eral, state, municipal and private authorities including property owners, property managers, and utilities in the drafting of their maintenance specifications.

1 . 3 A p p l i c a t i o n

ANSI A300 standards shall apply to any person or entity engaged in the business, trade, or performance of repairing, maintaining, or preserving trees, shrubs, or other woody plants.

1 . 4 I m p l e m e n t a t i o n

Specifications for tree maintenance should be writ-ten and administered by an arborist.

2 Part 1 – Pruning standards

2 . 1 P u r p o s e

The purpose of this document is to provide standards for developing specifications for tree pruning.

2 . 2 Reasons for pruning

The reasons for tree pruning may include, but are not limited to, reducing risk, maintaining or improv-ing tree health and structure, improving aesthetics, or satisfying a specific need. Pruning practices for agricultural, horticultural production, or silvicultural purposes are exempt from this standard.

2 . 3 Safe ty

2 . 3 . 1 Tree maintenance shall be performed only by arborists or arborist trainees who, through related training or on-the-job experience, or both, are famil-iar with the practices and hazards of arboriculture and the equipment used in such operations.

2 . 3 . 2 This standard shall not take precedence over arboricultural safe work practices.

2 . 3 . 3 Operations shall comply with applicable Occupational Safety and Health Administration (OSHA) standards, ANSI Z133.1, as well as state and local regulations.

3 Normative references

The following standards contain provisions, which, through reference in the text, constitute provisions of this American National Standard. All standards are subject to revision, and parties to agreements based on this American National Standard shall ap-ply the most recent edition of the standards indi-cated below.

ANSI Z60.1, Nursery stock

ANSI Z133.1, Tree care operations - Pruning, trim-ming, repairing, maintaining, and removing trees, and cutting brush - Safety requirements

29 CFR 1910, General industry 1)

29 CFR 1910.268, Telecommunications 1)

29 CFR 1910.269, Electric power generation, trans-mission, and distribution 1)

29 CFR 1910.331 - 335, Electrical safety-related work practices 1)

4 Definitions

4 . 1 anvil-type pruning tool: A pruning tool that

American National Standard for Tree Care Operations –

AMERICAN NATIONAL STANDARD ANSI A300 (Part 1)-2001 Pruning

Tree, Shrub, and Other Woody Plant Maintenance – Standard Practices (Pruning)

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has a sharp straight blade that cuts against a flat metal cutting surface, in contrast to a hook-and-blade-type pruning tool (4.21).

4 . 2 apical dominance: Inhibition of growth of lateral buds by the terminal bud.

4 . 3 arboriculture: The art, science, technology, and business of commercial, public, and utility tree care.

4 . 4 arborist: An individual engaged in the pro-fession of arboriculture who, through experience, edu-cation, and related training, possesses the compe-tence to provide for or supervise the management of trees and other woody plants.

4 . 5 arborist trainee: An individual undergoing on-the-job training to obtain the experience and the competence required to provide for or supervise the management of trees and other woody plants. Such trainees shall be under the direct supervision of an arborist.

4 . 6 branch bark ridge: The raised area of bark in the branch crotch that marks where the branch and parent meet.

4 . 7 branch collar: The swollen area at the base of a branch.

4 . 8 callus: Undifferentiated tissue formed by the cambium around a wound.

4 . 9 cambium: The dividing layer of cells that forms sapwood (xylem) to the inside and inner bark (phloem) to the outside.

4 . 1 0 cleaning: Selective pruning to remove one or more of the following parts: dead, diseased, and/ or broken branches (5.6.1).

4 . 1 1 climbing spurs: Sharp, pointed devices af-fixed to a climber’s boot used to assist in climbing trees. (syn.: gaffs, hooks, spurs, spikes, climbers)

4 . 1 2 closure: The process of woundwood cov-ering a cut or other tree injury.

4 . 1 3 crown: The leaves and branches of a tree measured from the lowest branch on the trunk to the top of the tree.

4 . 1 4 decay: The degradation of woody tissue caused by microorganisms.

4 . 1 5 espalier: The combination of pruning, sup-porting, and training branches to orient a plant in one plane (5.7.2).

4 . 1 6 establishment: The point after planting when a tree’s root system has grown sufficiently into the surrounding soil to support shoot growth and anchor the tree.

4 . 1 7 facility: A structure or equipment used to deliver or provide protection for the delivery of an essential service, such as electricity or communi-cat ions.

4 . 1 8 final cut: A cut that completes the removal or reduction of a branch or stub.

4 . 1 9 frond: A leaf of a palm.

4 . 2 0 heading: 1. Cutting a currently growing, or a 1-year-old shoot, back to a bud. 2. Cutting an older branch or stem back to a stub in order to meet a defined structural objective. 3. Cutting an older branch or stem back to a lateral branch not large enough to assume apical dominance in order to meet a defined structural objective. Heading may or may not be an acceptable pruning practice, de-pending on the application.

4 . 2 1 hook-and-b lade- type prun ing too l : A prun ing too l that has a sharp curved b lade that over laps a suppor t ing hook; in cont ras t to an anvi l - type pruning tool (4 .1 ) . ( syn . : by -pass p r u n e r )

4 . 2 2 interfering branches: Crossing, rubbing, or upright branches that have the potential to dam-age tree structure and/or health.

4 . 2 3 internodal cut: A cut located between lat-eral branches or buds.

4 . 2 4 lateral branch: A shoot or stem growing from a parent branch or stem.

4 . 2 5 leader: A dominant or co-dominant, upright s tem.

4 . 2 6 limb: A large, prominent branch.

4 . 2 7 lion’s tailing: The removal of an excessive number of inner, lateral branches from parent

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branches. Lion’s tailing is not an acceptable pruning practice (5.5.7).

4 . 2 8 mechanical pruning: A utility pruning tech-nique where large-scale power equipment is used to cut back branches (5.9.2.2).

4 . 2 9 parent branch or stem: A tree trunk, limb, or prominent branch from which shoots or stems grow.

4 . 3 0 peeling: For palms: The removal of only the dead frond bases at the point they make con-tact with the trunk without damaging living trunk tis-sue. (syn.: shaving)

4 . 3 1 petiole: A stalk of a leaf or frond.

4 . 3 2 phloem: Inner bark conducting tissues that transport organic substances, primarily carbohydrates, from leaves and stems to other parts of the plant.

4 . 3 3 pollarding: The maintenance of a tree by making internodal cuts to reduce the size of a young tree, followed by the annual removal of shoot growth at its point of origin (5.7.3).

4 . 3 4 pruning: The selective removal of plant parts to meet specific goals and objectives.

4 . 3 5 qualified line-clearance arborist: An in-dividual who, through related training and on-the-job experience, is familiar with the equipment and hazards in line clearance and has demonstrated the ability to perform the special techniques in-volved. This individual may or may not be currently employed by a line-clearance contractor.

4 . 3 6 qualified line-clearance arborist trainee:

An individual undergoing line-clearance training and who, in the course of such training, is familiar with the hazards and equipment involved in line clearance and has demonstrated ability in the per-formance of the special techniques involved. This individual shall be under the direct supervision of a qualified line-clearance arborist.

4 . 3 7 raising: Selective pruning to provide verti-cal clearance (5.6.3).

4 . 3 8 reduction: Selective pruning to decrease height and/or spread (5.6.4).

4 . 3 9 remote/rural areas: Locations associated with very little human activity, land improvement, or deve lopment .

4 . 4 0 restoration: Selective pruning to improve the structure, form, and appearance of trees that have been severely headed, vandalized, or dam-aged (5.7.4).

4 . 4 1 shall: As used in this standard, denotes a mandatory requirement.

4 . 4 2 should: As used in this standard, denotes an advisory recommendation.

4 . 4 3 stub: An undesirable short length of a branch remaining after a break or incorrect prun-ing cut is made.

4 . 4 4 thinning: Selective pruning to reduce den-sity of live branches (5.6.2).

4 . 4 5 throwline: A small, lightweight line with a weighted end used to position a climber’s rope in a t ree.

4 . 4 6 topping: The reduction of a tree’s size us-ing heading cuts that shorten limbs or branches back to a predetermined crown limit. Topping is not an acceptable pruning practice (5.5.7).

4 . 4 7 tracing: The removal of loose, damaged tis-sue from in and around the wound.

4 . 4 8 urban/residential areas: Locations, such as populated areas including public and private property, that are normally associated with human activi ty.

4 . 4 9 utility: An entity that delivers a public ser-vice, such as electricity or communications.

4 . 5 0 utility space: The physical area occupied by a utility’s facilities and the additional space re-quired to ensure its operation.

4 . 5 1 vista pruning: Selective pruning to allow a specific view (5.7.5).

4 . 5 2 watersprouts: New stems originating from epicormic buds. (syn.: epicormic shoots)

4 . 5 3 wound: An opening that is created when the bark of a live branch or stem is penetrated, cut, or removed.

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4 . 5 4 woundwood: Par t ia l ly d i f ferent ia ted t is -sue responsible for c losing wounds. Woundwood deve lops f rom ca l lus assoc ia ted wi th wounds.

4 . 5 5 xylem: Wood tissue. Active xylem is sap-wood; inactive xylem is heartwood.

4 . 5 6 young tree: A tree young in age or a newly transplanted tree.

5 Pruning practices

5 . 1 Tree inspection

5 . 1 . 1 An arborist or arborist trainee shall visu-ally inspect each tree before beginning work.

5 . 1 . 2 If a condition is observed requiring atten-tion beyond the original scope of the work, the con-dition should be reported to an immediate supervi-sor, the owner, or the person responsible for au-thorizing the work.

5 . 2 Tools and equipment

5 . 2 . 1 Equipment and work practices that dam-age living tissue and bark beyond the scope of the work should be avoided.

5 . 2 . 2 Climbing spurs shall not be used when climbing and pruning trees.

Except ions :

- when limbs are more than throwline distance apart and there is no other means of climbing the t ree;

- when the bark is thick enough to prevent dam-age to the cambium;

- in remote or rural utility rights-of-way.

5 . 3 Pruning cuts

5 . 3 . 1 Pruning tools used in making pruning cuts shall be sharp.

5 . 3 . 2 A pruning cut that removes a branch at its point of origin shall be made close to the trunk or parent limb, without cutting into the branch bark ridge or collar, or leaving a stub (see Figure 5.3.2).

5 . 3 . 3 A pruning cut that reduces the length of a branch or parent stem should bisect the angle be-tween its branch bark ridge and an imaginary line perpendicular to the branch or stem (see Figure 5.3.3).

5 . 3 . 4 The final cut shall result in a flat surface with adjacent bark firmly attached.

5 . 3 . 5 When removing a dead branch, the final cut shall be made just outside the collar of living t issue.

5 . 3 . 6 Tree branches shall be removed in such a manner so as not to cause damage to other parts of the tree or to other plants or property. Branches too large to support with one hand shall be precut to avoid splitting of the wood or tearing of the bark (see Figure 5.3.2). Where necessary, ropes or other equipment shall be used to lower large branches or portions of branches to the ground.

5 . 3 . 7 A final cut that removes a branch with a narrow angle of attachment should be made from the outside of the branch to prevent damage to the parent limb (see Figure 5.3.7).

5 . 3 . 8 Severed limbs shall be removed from the crown upon completion of the pruning, at times when the tree would be left unattended, or at the end of the workday.

Figure 5.3.2. – A pruning cut that removes a branch at its point of origin shall be made close to the trunk or parent limb, without cutting into the branch bark ridge or collar, or leaving a stub.

Branches too large to support with one hand shall be precut to avoid splitting of the wood or tear-ing of the bark.

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Figure 5.3.3. – A pruning cut that reduces the length of a branch or parent stem should bisect the angle between its branch bark ridge and an imaginary line perpendicular to the branch or s t e m .

Figure 5.3.7. – A final cut that removes a branch with a narrow angle of attachment should be made from the outside of the branch to prevent dam-age to the parent l imb.

5 . 4 Wound treatment

5 . 4 . 1 Wound treatments should not be used to cover wounds or pruning cuts, except when recom-mended for disease, insect, mistletoe, or sprout con-trol, or for cosmetic reasons.

5 . 4 . 2 Wound treatments that are damaging to tree tissues shall not be used.

5 . 4 . 3 When tracing wounds, only loose, dam-aged tissue should be removed.

5 . 5 Pruning objectives

5 . 5 . 1 Pruning objectives shall be established prior to beginning any pruning operation.

5 . 5 . 2 To obtain the defined objective, the growth cycles and structure of individual species and the type of pruning to be performed should be considered.

5 . 5 . 3 Not more than 25 percent of the foliage should be removed within an annual growing sea-son. The percentage and distribution of foliage to be removed shall be adjusted according to the plant’s species, age, health, and site.

5 . 5 . 4 Not more than 25 percent of the foliage of a branch or limb should be removed when it is cut back to a lateral. That lateral should be large enough to assume apical dominance.

5 . 5 . 5 Pruning cuts should be made in accordance with 5.3 Pruning cuts .

5 . 5 . 6 Heading should be considered an accept-able practice for shrub or specialty pruning when needed to reach a defined objective.

5 . 5 . 7 Topping and lion’s tailing shall be consid-ered unacceptable pruning practices for trees.

5 . 6 Pruning types

Specifications for pruning should consist of, but are not limited to, one or more of the following types:

5 . 6 . 1 Clean: Cleaning shall consist of selective pruning to remove one or more of the following parts: dead, diseased, and/or broken branches.

5 . 6 . 1 . 1 Location of parts to be removed shall be specif ied.

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5 . 6 . 1 . 2 Size range of parts to be removed shall be speci f ied.

5 . 6 . 2 T h i n : Thinning shall consist of selective pruning to reduce density of live branches.

5 . 6 . 2 . 1 Thinning should result in an even distribu-tion of branches on individual limbs and through-out the crown.

5 . 6 . 2 . 2 Not more than 25 percent of the crown should be removed within an annual growing sea-son.

5 . 6 . 2 . 3 Location of parts to be removed shall be speci f ied.

5 . 6 . 2 . 4 Percentage of foliage and size range of parts to be removed shall be specified.

5 . 6 . 3 R a i s e : Raising shall consist of selective pruning to provide vertical clearance.

5 . 6 . 3 . 1 Vertical clearance should be specified.

5 . 6 . 3 . 2 Location and size range of parts to be re-moved should be specified.

5 . 6 . 4 R e d u c e : Reduction shall consist of selective pruning to decrease height and/or spread.

5 . 6 . 4 . 1 Consideration shall be given to the ability of a species to tolerate this type of pruning.

5 . 6 . 4 . 2 Location of parts to be removed and clear-ance should be specified.

5 . 6 . 4 . 3 Size range of parts should be specified.

5 . 7 Specialty pruning

Consideration shall be given to the ability of a spe-cies to tolerate specialty pruning, using one or more pruning types (5.6).

5 . 7 . 1 Young trees

5 . 7 . 1 . 1 The reasons for young tree pruning may inc lude, but are not l imi ted to , reduc ing r isk , mainta in ing or improv ing t ree heal th and s t ruc-ture , improv ing aesthet ics , or sat is fy ing a spe-c i f ic need.

5 . 7 . 1 . 2 Young trees that will not tolerate repetitive pruning and have the potential to outgrow their space should be considered for relocation or removal.

5 . 7 . 1 . 3 At planting

5 . 7 . 1 . 3 . 1 Pruning should be limited to clean-ing (5.6.1).

5 . 7 . 1 . 3 . 2 Branches should be retained on the lower trunk.

5 . 7 . 1 . 4 Once established

5 . 7 . 1 . 4 . 1 Cleaning should be performed (5.6.1) .

5 . 7 . 1 . 4 . 2 Rubbing and poorly attached branches should be removed.

5 . 7 . 1 . 4 . 3 A central leader or leader(s) as ap-propriate should be developed.

5 . 7 . 1 . 4 . 4 A strong, properly spaced scaffold branch structure should be selected and main-ta ined .

5 . 7 . 1 . 4 . 5 Interfering branches should be re-duced or removed.

5 . 7 . 2 E s p a l i e r

5 . 7 . 2 . 1 Branches that extend outside the desired plane of growth shall be pruned or tied back.

5 . 7 . 2 . 2 Ties should be replaced as needed to pre-vent girdling the branches at the attachment site.

5 . 7 . 3 P o l l a r d i n g

5 . 7 . 3 . 1 Consideration shall be given to the ability of the individual tree to respond to pollarding.

5 . 7 . 3 . 2 Management plans shall be made prior to the start of the pollarding process for routine re-moval of watersprouts.

5 . 7 . 3 . 3 Internodal cuts shall be made at specific locations to start the pollarding process. After the initial cuts are made, no additional internodal cut shall be made.

5 . 7 . 3 . 4 Watersprouts growing from the cut ends of branches (knuckles) should be removed annually during the dormant season.

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5 . 7 . 4 R e s t o r a t i o n

5 . 7 . 4 . 1 Restoration shall consist of selective prun-ing to improve the structure, form, and appearance of trees that have been severely headed, vandal-ized, or damaged.

5 . 7 . 4 . 2 Location in tree, size range of parts, and percentage of watersprouts to be removed should be specified.

5 . 7 . 5 Vista pruning

5 . 7 . 5 . 1 Vista pruning shall consist of selective prun-ing to allow a specific view.

5 . 7 . 5 . 2 Size range of parts, location in tree, and percentage of foliage to be removed should be speci-f ied.

5 . 8 Palm pruning

5 . 8 . 1 Palm pruning should be performed when fronds, fruit, or loose petioles may create a dan-gerous condition.

5 . 8 . 2 Live healthy fronds, initiating at an angle of 45 degrees or greater from horizontal, with frond tips at or below horizontal, should not be removed.

5 . 8 . 3 Fronds removed should be severed close to the petiole base without damaging living trunk t issue.

5 . 8 . 4 Palm peeling (shaving) should consist of the removal of only the dead frond bases at the point they make contact with the trunk without dam-aging living trunk tissue.

5 . 9 Utility pruning

5 . 9 . 1 G e n e r a l

5 . 9 . 1 . 1 The purpose of utility pruning is to prevent the loss of service, comply with mandated clear-ance laws, prevent damage to equipment, avoid access impairment, and uphold the intended us-age of the facility/utility space.

5 . 9 . 1 . 2 Only a qualified line clearance arborist or line clearance arborist trainee shall be assigned to line clearance work in accordance with ANSI

Z133.1, 29 CFR 1910.331 – 335, 29 CFR 1910.268

or 29 CFR 1910.269.

5 . 9 . 1 . 3 Utility pruning operations are exempt from requirements in 5.1 Tree Inspection:

5 . 1 . 1 An arborist or arborist trainee shall visually inspect each tree before beginning work.

5 . 1 . 2 If a condition is observed requiring atten-tion beyond the original scope of the work, the con-dition should be reported to an immediate supervi-sor, the owner, or the person responsible for au-thorizing the work.

5 . 9 . 1 . 4 Safety inspections of the work area are re-quired as outlined in ANSI Z133.1 4.1.3, job brief-i ng.

5 . 9 . 2 Utility crown reduction pruning

5 . 9 . 2 . 1 Urban/residential environment

5 . 9 . 2 . 1 . 1 Pruning cuts should be made in accordance with 5.3, Pruning cuts. The following requirements and recommendations of 5.9.2.1.1 are repeated from 5.3 Pruning cuts.

5 . 9 . 2 . 1 . 1 . 1 A pruning cut that removes a branch at its point of origin shall be made close to the trunk or parent limb, without cutting into the branch bark ridge or collar, or leaving a stub (see Figure 5.3.2).

5 . 9 . 2 . 1 . 1 . 2 A pruning cut that reduces the length of a branch or parent stem should bisect the angle between its branch bark ridge and an imagi-nary line perpendicular to the branch or stem (see Figure 5.3.3).

5 . 9 . 2 . 1 . 1 . 3 The final cut shall result in a flat surface with adjacent bark firmly attached.

5 . 9 . 2 . 1 . 1 . 4 When removing a dead branch, the final cut shall be made just outside the collar of liv-ing tissue.

5 . 9 . 2 . 1 . 1 . 5 Tree branches shall be removed in such a manner so as not to cause damage to other parts of the tree or to other plants or property.

Branches too large to support with one hand shall be precut to avoid splitting of the wood or tearing of the bark (see Figure 5.3.2). Where necessary, ropes or other equipment shall be used to lower large branches or portions of branches to the ground.

5 . 9 . 2 . 1 . 1 . 6 A final cut that removes a branch

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with a narrow angle of attachment should be made from the bottom of the branch to prevent damage to the parent limb (see Figure 5.3.7).

5 . 9 . 2 . 1 . 2 A minimum number of pruning cuts should be made to accomplish the purpose of facil-ity/utility pruning. The natural structure of the tree should be considered.

5 . 9 . 2 . 1 . 3 Trees directly under and growing into facility/utility spaces should be removed or pruned. Such pruning should be done by removing entire branches or by removing branches that have laterals growing into (or once pruned, will grow into) the facility/utility space.

5 . 9 . 2 . 1 . 4 Trees growing next to, and into or toward facility/utility spaces should be pruned by re-ducing branches to laterals (5.3.3) to direct growth away from the utility space or by removing entire branches. Branches that, when cut, will produce watersprouts that would grow into facilities and/or utility space should be removed.

5 . 9 . 2 . 1 . 5 Branches should be cut to laterals or the parent branch and not at a pre-established clearing limit. If clearance limits are established, pruning cuts should be made at laterals or parent branches outside the specified clearance zone.

5 . 9 . 2 . 2 Rural/remote locations – mechanical p r u n i n g

Cuts should be made close to the main stem, out-side of the branch bark ridge and branch collar. Pre-cautions should be taken to avoid stripping or tear-ing of bark or excessive wounding.

5 . 9 . 3 Emergency service restoration

During a utility-declared emergency, service must be restored as quickly as possible in accordance with ANSI Z133.1, 29 CFR 1910.331 – 335, 29 CFR 1910.268, or 29 CFR 1910.269. At such times it may be necessary, because of safety and the ur-gency of service restoration, to deviate from the use of proper pruning techniques as defined in this standard. Following the emergency, corrective pruning should be done as necessary.

Licensed to Tanya Gaona. ANSI order X_35662. Downloaded 12/21/2007 10:59 AM. Single user license only. Copying and networking prohibited.

Annex A (informative)

Reference publications

International Society of Arboriculture (ISA). 1995. Tree Pruning Guidelines . Savoy, IL: International Society of Arboriculture (ISA).

Licensed to Tanya Gaona. ANSI order X_35662. Downloaded 12/21/2007 10:59 AM. Single user license only. Copying and networking prohibited.