Large Trees- Trees with a mature height and spread of more than 40 feet, such as: Maple, Willow, Cottonwood, Spruce, Birch. Plant no closer than 50 feet from power lines. Medium Trees- Mature height and spread from 15 to 40 feet, such as: Dogwood. Plant no closer than 30 feet from power lines. Small Trees- Mature height of 15 feet or less, such as: Lilac, Crabapple. Plant within the range of 20 feet from power lines.

Planting Trees Near Power Lines

Trees beautify our neighborhoods, when planted:

  • In the right spot, trees can help lower energy bills
  • In the wrong place, trees can be a hazard…especially to power lines

When Planting Trees

  • Avoid planting trees within 20 feet of power lines

When Planting Within 20 feet Is Unavoidable

Only plant and maintain the following within the 20-foot zone, on either side of power lines:

  • Grass
  • Flowers
  • Hedges
  • Shrubs

For your reference, Flathead Electric maintains a list of Small Trees – Maturing at Less Than 15 Feet Tall (PDF). Thank you for helping us continue to provide you with reliable, efficient service in the future!

Plan Before You Plant Video

Plan Before You Plant from Flathead Electric on Vimeo.

Maintaining Trees Near Power Lines

When it is time to trim, cut or plant your trees it may seem faster and easier to do it yourself rather than to contact a professional. Even if you are considering having professional arborists/landscapers perform your upkeep, it’s important to contact us and Montana 811 (Just dial 811, or go to the Montana 811 website) for a free line locator before, just to be safe.

Before You Trim

  • We encourage you to call the Co-op before you trim your trees so we can:
    • Locate high voltage power lines
    • Anticipate safety issues
  • If you have a tree or trees growing near or into our primary, high voltage power lines, we will trim or even cut the tree, free of charge to you
  • Trees that grow too close to power lines can be an extreme safety hazard for children and tree trimmers
  • To meet national safety codes, only line clearance certified tree trimmers are allowed to work on a tree within 10 feet of an energized, high-voltage line
  • Flathead Electric tree trimming crews, or contract trimming crews are trained in the latest pruning techniques as presented by the International Society of Arboriculture

We understand that you take pride in homeownership and the maintenance of your land, but following these instructions are in the best interest of public safety. They also provide our workers with a safe working environment, which can mean the difference between life and death.

Please call Flathead Electric at (406) 751-4483 and ask for the Vegetation Management Department if you have questions.

Tree FAQs

The following FAQs were developed by the Utility Arborist Association to provide an overview of how an electric utility uses tree maintenance techniques to achieve their goal to provide safe, reliable service.

Why do electric utilities prune trees?

It’s a matter of safety and providing reliable power for the members we serve.

Safety—Utility vegetation maintenance reduces electric hazard risk to the public by:

  • Providing separation between wires and vegetation to eliminate potential electrical shock
  • Reducing potential wildfire hazards from tree/wire conflicts

Reliability—Trees are among the most common causes of utility service interruptions. Trees that are too close to power lines can interfere with electric service; especially when weather brings lightning, wind, ice, or wet snow.

How much will be cut from my tree?

Typically, a qualified utility forester or vegetation manager prescribes the amount and type of pruning necessary based on:

  • Tree growth rate and structure
  • Wind direction
  • Tree species: strong or weak wooded
  • Tree health or vigor
  • Environmental factors
  • Water sources
  • Proximity of tree to wires and line configuration— higher voltage lines require greater clearance
What is directional pruning?

Directional pruning:

  • Removes branches growing toward the power lines while leaving those that are growing away
  • Is the most appropriate pruning method for utility line clearance

How will a tree look after it is directionally pruned?

  • Trees growing directly under power lines may appear U or V-shaped (crown reduction or throughpruning)
  • Trees growing alongside power lines may appear L- shaped, or one side may be completely removed (side pruning)
  • The tree may often appear misshapen but this pruning is being performed to provide for safety and service reliability, not for aesthetic purposes
  • Trees growing near the power lines will never have the potential to grow with a “natural” shape

Do Not Top Trees! Also called ‘roundingover’. It involves cutting branches to stubs or lateral points that are not large enough to grow successfully.

  • This is not directional pruning
  • Not an acceptable pruning practice

It can:

  • Severely weaken the tree
  • Kill some species
What specific pruning guidelines are followed?

The ANSI A-300 Part 1: Tree, Shrub and Other Woody Plant Maintenance—Standard Practices, Pruning are:

  • Accepted guidelines
  • Endorsed by the International Society of Arboriculture (ISA)

They promote directional pruning methods which:

  • Minimize pruning stress
  • Focuses on tree health while obtaining necessary clearance from power lines
How are trees pruned in a remote or wooded area?

In remote/rural locations, utilities:

  • Often utilize mechanical equipment to increase efficiency and worker safety
    • Large saws mounted on high-reaching booms can be used to prune the sides of right-of-way corridors
    • In some cases, saws are suspended from helicopters
  • Chemical application is another method of side pruning
    • Herbicides are applied to the foliage of selected branches growing into the right-of-way corridor
    • The treated branches eventually die and are shed by the tree

When using this equipment it is understood that the quality of the cuts can be less than those made by hand. Nevertheless, efforts are made to avoid unnecessary damage to the tree.

Who will be performing the work on my trees?

Only qualified utility line clearance professional arborists who meet OSHA qualifications are legally permitted to work within 10 feet of power lines or work on a tree that has branches within 10 feet of power lines.

Line clearance arborists are trained to:

  • Prune trees according to American National Standards Institute (ANSI) A-300 pruning standards
  • Follow industry best practices, which helps preserve the health of trees


Homeowners should:

  • Never hire a private tree contractor to work within 10 feet of power lines
  • Never attempt to do the work themselves
  • Always contact the utility for information first