Best Management Practices in Utility
Arboriculture
Janet L. Brown, Project Coordinator
PSE Vegetation Management
ISA Certified Arborist/Tree Risk Assessor
June 13, 2012
Perception of the Utility Arborist?
2
Today’s Utility Arborist
 Promotes
professionalism
 Has Credentials
 Informs the
public: what we
are doing and
why
 Uses “Best
Management
Practices”
3
 What are “best
management
practices?”
 How are they
developed?
 How should they
be used?
4
Where We Have Been
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A Shade Tree Guide
By
ALFRED GASKILL
State Forester [New Jersey]
Published May, 1918
available on Google
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A Shade Tree Guide by Alfred Gaskill
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8
By George Blair
Chief Forester
Consumers Power Company,
Jackson, Michigan
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NRECA Recommendation (to ~1998)
 Rural Electric illustration here
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Have times changed
since 1918?
One thing remains the
same:
 Vegetation must be
maintained
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Stay on
cycle
Trees not maintained on cycle will overtake the lines. Recovery may require extensive
pruning or tree removal.
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Not doing the work can lead to serious
consequences…
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Regulations, Trimming “Rights”, & Utility Standards


The WUTC regulates private, investor-owned electric and natural gas utilities in
Washington. It is the commission's responsibility to ensure regulated companies provide safe
and reliable service to customers at reasonable rates, while allowing them the opportunity to
earn a fair profit.
WAC 296-45-045 NESC applicable. (1) All electric utilities and entities operating
transmission and distribution facilities within the state of Washington must design, construct,
operate, and maintain their lines and equipment according to the requirements of the 2002
National Electrical Safety Code (NESC) (ANSI-C2), parts (1), (2), and (3).

NESC states:
218. Tree Trimming
1) Trees that may interfere with ungrounded supply conductors should be trimmed or
removed. Note: Normal tree growth, the combined movement of trees and conductors under
adverse weather conditions, voltage, and sagging of conductors at elevated temperatures are
among the factors to be considered in determining the extent of trimming required.
2) Where trimming or removal is not practical, the conductor should be separated from the
tree with suitable material or devices to avoid conductor damage by abrasion and grounding
of the circuit through the tree.

Vegetation Management Standards
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Utility Pruning
Best Management Practices
 Based on ANSI A300 Part 1
 Available from ISA
 www.isa-arbor.com
Describes:
 Purpose of utility pruning
 Tools and equipment
 Pruning cuts
 Pruning method
 Tree response
 Cycle pruning
 Benefits
 Role of Tree Growth
Regulators
 “Recovery” pruning
 Palm pruning
 Pruning vs. removal
 Remote/rural locations
 Emergency service restoration
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All trees are not the same!
Consider variables such as:
 Species
characteristics
 Shape
 Natural structure
 Wood strength




Growth rate
Reaction to pruning
Overall tree health
Length of time until
next pruning
 All trees are not
the same!
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Rounding over, topping or stubbing damages trees,
results in a flush of fast growing sprouts and is now a
discredited practice
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“Best Management Practices”
How do we apply written guidelines to a living, changing resource that is
unique on every site?





Every tree is different
Every arborist is different
Objectives vary
Arborists must be professional and able to make good decisions
Written standards, best management practices and
specifications provide guidelines that protect both the client and
the arborist.
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Directional Pruning vs. Removal/Replacement
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Find Common Ground
 Some practices are
generally superior
 Some practices are
inferior, destructive, or
otherwise discredited
 Often what is the “Best”
practice depends on the
circumstances
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Remember:
 Best Management
Practices are guidelines
 Every situation is
different!
 Professionals must
determine what practice
is “best” in any given
location!
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Thank you!
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