NorthWestern Energy is interested in where you plant trees and how you trim them. Trees that grow too close or into power lines can cause electric outages or service interruptions for you and your neighbors. In addition, trees conduct electricity and create potential safety hazards when branches grow too close to power lines. For example, an unsuspecting child could climb an overgrown tree and come in contact with a live power line and risk electrocution.
Before you plant a tree, get the facts. Find out how the tree will look 5, 10, or even 50 years into the future. Knowing what height a tree will reach at maturity will help you make the right decisions now. Carefully planted trees stay out of power lines and retain their natural beauty while saving the costs of trimming them from power lines.
Utilities and, therefore, their customers pay millions of dollars each year just to trim trees. And even a well trimmed tree may not be as fetching as it was before the saw. Carefully planted trees, on the other hand, stay out of lines and retain their natural beauty while saving money on everyone's electric bill.
- When you buy your next tree, ask the gardener if the tree is safe to plant around power lines.
- Trees, whose mature height does not exceed 20 feet, fit comfortably under power lines. It is unlikely they will ever have to be trimmed to protect public safety and electric reliability.
- Trees with mature heights of 30 to 40 feet need to be set at least 15 to 20 feet from the outside line of a power pole. Trees that grow taller than that, should be planted more than 35 feet from the home and need to give power lines a wide berth.
Lines brushed by a tree limb can cause an outage, illustrating that a tree or branch does not necessarily have to fall to interrupt electric service. Our tree trimming program is one way NorthWestern Energy works to protect the safety of its employees and the public while providing reliable electric service.
Trimming trees is the homeowners responsibility. However, before you trim a tree near a power line, call us toll free at (800) 245-6977. We'll stop by to make sure it is safe for you to proceed or if we need to trim your tree for you. Our primary concern is your safety.
NorthWestern Energy’s tree trimming guidelines have been designed to reflect the recommendations of the National Arborist Association and ANSI Standard A300. Sometimes customers wonder about the techniques we use to trim trees. Here is an overview of our two primary trimming methods, based on the work of Dr. Alex L. Shigo, the author of Pruning Trees Near Electric Utility Lines: A Field Pocket Guide For Qualified Line-Clearance Workers.
- Drop Crotching or V Pruning is used whenever feasible to retain as much of the natural shape of the tree as possible. This method thins out a tree by removing unnecessary branches from the middle.
- Directional Trimming involves leaving branches that grow away from power lines in place while removing branches that grow toward the lines. This method promotes growth away from the power lines and reduces the amount of trimming necessary from year to year. All cuts are at tree nodes, the location where tree branches naturally shed.
Proper trimming may look severe at first, but trees will re-grow at a normal rate and the re-growth won’t be accompanied by profuse sprouting. These methods help maintain the tree’s health because fewer cuts are used, and the ones made are located near the branch base or collar to facilitate rapid healing. Precautions also are taken to avoid stripping or tearing of the tree’s bark when cutting. Our goal is to help trees be as healthy, safe, and attractive as possible.
We appreciate your cooperation when it becomes necessary to trim any trees interfering with electric power lines.
Other Tree Considerations
Never build a tree house, climb in, or play in any tree that is located near a power line. Never attach any steps, ladders, ropes swings or any objects that could assist in ascending a tree where power lines are present.
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