Tree Trimming Near Power Lines
Why do electric utilities prune trees?
Safety - Utility vegetation maintenance reduces electric safety risk to the public by:
- providing a minimum separation between the lines and vegetation,
- reducing potential wildfire hazards from tree / wire conflicts and downed power lines, potential electrical shock,
- maintaining services to vital infrastructure such as traffic signals, airports, water and sewer pumping stations as well as hospitals, nursing homes, fire and police stations.
Reliability - Trees are among the most common cause of utility service interruptions. Trees that are too close to power lines can interfere with electric service, especially when weather brings lightning, high winds, ice or wet snow.
Utilities have a preventative maintenance program that removes branches, vines, trees and brush from electrical equipment and energized conductors to help the overall quality of your electrical service.
The utility only removes vegetation that can potentially cause a safety hazard or an electrical outage when it grows into or contacts power lines due to weather or poor tree health.
Note: Homeowners should never hire a private tree contractor to work within 10 feet of energized conductors or attempt to do this work themselves.
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Which pruning guidelines do the utilities follow?
The utilities follow the American National Standard Institute (ANSI) A-300 Part 1: Tree, Shrub and Other Woody Plant Maintenance - Standard Practices, Pruning.
These guidelines, endorsed by the international Society of Arboriculture (ISA), promote natural target pruning and directional pruning methods which minimize pruning stress to focus on tree health while obtaining needed clearance from the power lines.
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My trees are not even touching any electrical wires. Why do they want to prune them?
Electric utilities are proactive and prune trees BEFORE they pose a risk to the power lines. Trees and branches sway, vegetation and the environment are dynamic, Factors such as trees swaying in the wind, sagging with ice or snow and uprooting in storms are examples of problems that can occur without warning. Tall growing vegetation under power lines can also pose a threat as the conductors can sag during high temperatures.
Addressing vegetation before it causes a problem is ideal to direct growth away from electrical conductors and facilities. Depending on tree species and location, it may take years before a tree presents a potential safety or reliability risk. However, fast growing trees planted near the power lines will need to be pruned or removed completely as they mature.
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What is a line-clearance tree contractor?
As defined by Occupational Safety and Health Administration (OSHA), it is a company that is qualified to maintain trees near power lines. These companies employ qualified line-clearance arborists who receive ongoing electrical safety training as well as equipment maintenance and inspection programs to ensure tools are non-conductive for arborists who routinely work near energized power lines.
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The right tree in the right place
Planting the right tree in the right place can increase property value and energy efficiency of your home and minimize property damage and power outages caused when trees come into contact with power lines. When planting a new tree, consider where you are placing it and what the tree will look like in 10 or 20 years. Look up from the proposed planting site and see if there are wires overhead or nearby. Also, don't forget to check for underground utilities prior to planting.
Learn what the City of Tallahassee Electric Utility is doing to protect our power lines.
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Language taken from the "Utility Pruning of Trees" brochure courtesy of the Utility Arborist Association.