Tree Planting & Pruning
Trees that grow too close to power lines can cause outages, start fires or create other hazardous conditions. Generally, we remove trees that pose a serious threat to safety and electric service. Not only does this work help maintain electric safety and service reliability, it is required by state and federal regulations.
We take pride in having a professional tree maintenance program. In fact, we've been recognized with the Tree Line USA award by the National Arbor Day Foundation for our vegetation management and tree-pruning practices.
For information about the types of trees to plant near power lines:
To learn more, click on any section or question below; click on it again to "close" it.
- How do we prune?
We hire professional arborists to maintain a safe corridor around power lines. Our arborists and members of our tree pruning crews are certified by the International Society of Arboriculture. The tree's species, structure and the strength of wood are all considered when trees are pruned.
In addition to pruning, trees not intentionally planted as part of the landscape that measure less than six inches in diameter at 4.5 feet high will be removed and treated with herbicide.
If you'd like a tree pruned or removed for landscaping purposes, you'll need to hire a private tree removal contractor to perform the work. If necessary, we can disconnect a service line for their workers' safety.
- How much do we prune?
Pruning clearances depend on tree species and growth patterns and the voltage of nearby power lines. Around distribution lines, which are typically found in neighborhoods, we provide at least 10 feet of clearance. Fast-growing species (willow, Siberian elm, cottonwood and boxelder) require 14 feet of clearance while slow-growing species (spruce and oak) require at least 10 feet of clearance.
Here are some shapes you may expect from properly pruned trees:
- Tree removal
Sometimes the best solution to tree and power line conflicts is tree removal. We work with neighborhoods to remove problem trees, particularly in cases where they require repeated pruning. Tree removal is especially important where pruning alone cannot achieve safe clearance from power lines.
Rocky Mountain Power seeks the property owner's written permission prior to tree removal. Coupons are also provided to help landowner's buy low-growing replacement trees. These coupons are redeemable at local nurseries.
In the cases where sites are not suitable for pruning, we use mowers to remove the trees. Mowing sites often have dense populations of trees with straight trunks, such as pines or other conifers, which cannot be pruned to grow around power lines. This also helps reduce fire risk and clears the view for motorists.
- Tree planting tips
To reduce the need for future pruning, be sure you choose an appropriate tree for the space (especially around power lines). Some things to keep in mind as you're planting:
- Low-growing trees (under 25 feet when mature) may be planted adjacent to overhead power lines.
- Plant tall-growing trees (over 25 feet when mature) at least 25 feet away from overhead power lines.
- Trees that grow taller than 35 feet when mature should be planted 50 feet away from overhead lines.
- Plant trees and shrubs at least 10 feet away from ground-mounted transformers.
- Call 811 at least 48 hours before you plant to have your underground utilities located.
- Planting trees for energy efficiency
Planting trees in certain places around your home can help keep you comfortable and keep your energy costs down. Here are some ways to plant trees and save:
- Plant deciduous trees facing southeast and southwest for summer shade and winter sun.
- Shrubs and small trees can be placed to shade air conditioners and heat pumps. However, be careful not to plant too close to the unit, blocking air flow. Keep units free of leaves and needles.
- Plant a combination of evergreen trees and shrubs on the side of your home that blocks cold winter winds.
- Safety and working around electricity
When working outside with antennas, ladders and long-handled tools, remember to always look up to see if power lines are near. Never trim limbs or remove trees around power lines, and do not climb utility poles or trees near power lines for any reason.
- Tree clearances around high-voltage transmission lines
Trees typically must be removed around high-voltage transmission lines to protect the safety and reliability of electric service. Trees that grow too close to high-voltage power lines create hazardous conditions that can cause forest and brush fires, endanger homes, interrupt electric service and contribute to a catastrophic failure of the power grid.
Work will either be done by manual hand crew or by machine, based on the terrain. In either case, where trees and brush are removed, logs will be left for the landowner's use. Resulting brush and limbs will be cut to within 18 inches of the ground.
The figure below shows the areas around the power lines and towers that should be kept clear. We work to keep the wire zone clear of trees and fast-growing vegetation. Utility-friendly trees are acceptable in the border zone. Any imminently hazardous trees in any zone will be removed for your safety and the integrity of our system.