Jan 15, 2016
Best Management Practices in Utility Arboriculture
June 13, 2012
Janet L. Brown, Project CoordinatorPSE Vegetation ManagementISA Certified Arborist/Tree Risk Assessor
Perception of the Utility Arborist?
Today’s Utility Arborist
Has Credentials Informs the
public: what we are doing and why
Uses “Best Management Practices”
What are “best
How are they
How should they
Where We Have Been
A Shade Tree GuideBy
State Forester [New Jersey]
Published May, 1918
available on Google
A Shade Tree Guide by Alfred Gaskill
By George BlairChief Forester
Consumers Power Company, Jackson, Michigan
NRECA Recommendation (to ~1998)
Rural Electric illustration here
Have times changed since 1918?
One thing remains the same:
Vegetation must be maintained
Trees not maintained on cycle will overtake the lines. Recovery may require extensive pruning or tree removal.
Stay on cycle
Not doing the work can lead to serious consequences…
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
Utility Pruning Best Management Practices
Based on ANSI A300 Part 1 Available from ISA www.isa-arbor.comDescribes:
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
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
All trees are not the same! Consider variables such as:
Rounding over, topping or stubbing damages trees, results in a flush of fast growing sprouts and is now a discredited practice
“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.
Directional Pruning vs. Removal/Replacement
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
Best Management Practices are guidelines
Every situation is different!
Professionals must determine what practice is “best” in any given location!