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Why do you prune trees from power lines?
What companies do you contract with to do tree trimming?
Why do you need to prune so much of the tree? Can you shape trees for a better look?
Trees are the leading cause of power outages in our region. We prunes trees to promote reliable electrical service and to maintain a safe environment. Trees that grow into the power lines can cause problems in three ways:
Safety - Trees directly touching power lines can put stress on live wires and cause branches to burn and fall to the ground, sometimes causing fires in trees or nearby buildings. Trees growing close to power lines are dangerous because they create a potential path for electricity to travel to the ground. People that come into contact with this path (by touching, climbing, trimming, or cutting down the trees) put themselves at serious risk of being electrocuted or receiving significant electrical burns.
Storm-related outages - Wind, snow, and ice often damage trees. Branches, limbs and entire trees can fall on power lines resulting in power outages that can last for days.
Voltage loss - Trees touching power lines drain electricity off the electrical system resulting in voltage loss. Low voltage can damage motor-driven appliances in homes, such as refrigerators or washing machines, and sensitive electronics such as computers.
Our primary goal is to deliver safe and reliable electric service to our customers. In order to accomplish this, we need to maintain a safe distance between trees and power lines. The minimum clearance for most power lines is 10 feet.
Why don't you prune less off the tree and come back more often? Wouldn't this resolve the problem of badly shaped trees and trees in the lines?
We employ a team of arborists to ensure that proper pruning techniques are used to keep your tree alive, healthy, and out of harm's way. The pruning methods we use are endorsed by the International Society of Arboriculture. Although the initial prune with the directional pruning technique may appear severe, this method is recommended over topping or rounding-over trees. Directional-pruned trees are less susceptible to disease and insect problems, and the overall structure of the tree is stronger, more resistant to high winds and heavy ice. Directional pruning removes only those branches that pose a threat to power lines. Future growth is directed away from the power lines.
With over 1,700 miles of distribution power lines and over 420,000 customers, to keep the cost of power low to our customers, trees are pruned on a 4-year pruning cycle.
My trees aren't touching the lines, so why do you have to prune them?
We consider several factors when determining whether to prune a tree. Will strong winds cause the tree to make contact with the wires? Will movement in the wires, such as sagging due to high temperatures, cause the wires to contact the tree? Will wet rainy weather cause branches to droop? Your trees may not be touching the wires now, but they may before the next pruning cycle. We plan ahead for potential problems.
Do you prune trees from the wire that runs from the pole to my house?
When do you remove trees?
We prunes trees located between poles and the first 10 feet from where they attach to utility poles or service bridles. Maintaining clearance after the first 10 feet is the property owner's responsibility. This is not a high-voltage line, however, we recommend that you hire a professional service to do the pruning. Seattle City Light will provide a 24-hour disconnect so that this work can be done safely. Please use the following contact numbers for requesting this service.
|Location of property
|North of Denny
|South of Denny
If a tree poses a hazard to safety and property, or if pruning will undermine the health and overall stability of the tree, we work with the property owner to remove it. Unless there is an emergency, we will contact you in person or in writing before removing a tree from your property.
Trees in the lines wouldn't be a problem if you had underground lines. Why don't you put all your lines underground?
Customers sometimes ask us to remove a tree rather than prune it. We evaluate these requests on a case-by-case basis. In some situations, we will remove the tree.
For customers living in Seattle, we offer replacement trees, watering bags and expert advice through our partnership with the Seattle reLeaf's Trees for Neighborhoods Program. Customers living outside of Seattle are offered certificates for free trees redeemable at any nursery that is a member of the Washington State Nursery and Landscape Association. We also partner with the Seattle Department of Transportation Urban Forestry on community planting and site specific tree replacement projects.
There are a number of obstacles to placing all power lines underground. Existing trees and their root systems would be impacted, undermining the health and stability of the trees. Considerable expense, time, and disruption would be involved in trenching through existing road systems and landscapes. The cost of designing, engineering, and installing an underground system in an established neighborhood is very high. Customers would have to pay for an underground system.
Do you remove the debris after you prune?
In general, maintenance, repair, and rebuilding underground systems are more complex and expensive because the lines and structures are buried and hidden from view and not easily accessible. Also, if there is a fire in an underground vault, our crews cannot make repairs until it is safe to enter the area.
Normally our crews remove tree limbs and the debris created. The logs are cut into fireplace lengths and left by the right-of-way for the customer to enjoy. Generally, cut logs are left for the public if the customer does not want it.
I hired a tree company to prune/remove my tree and they say they can't because it's too close to the lines - what do I do now?
When tree debris is caused by a severe storm we are not always able to remove it. In these situations, crews cut broken and uprooted trees so they can access the damaged area to make repairs. Brush and wood may be left at the site so that they can proceed with other restoration work.
Only Qualified Line Clearance Tree Trimmers may work in proximity of our distribution or transmission power lines. If you want to have a tree that is too close to power lines removed or pruned we will perform a "make ready" at no charge to you, assuming all necessary permits are in place. This means we will remove as much of the tree as necessary to eliminate the potential electrical hazard to a non-Qualified Line Clearance Tree Trimmer, making the tree "ready" for removal or pruning. As with all other work, Seattle City Light will remove all brush leaving burnable firewood on site.
Can I prune my own trees?
Do you have information about the right trees and shrubs to plant under the lines?
State and federal safety regulations require that anyone working within 10 feet of a high-voltage electrical line must have proper training and certification. Most private tree companies do not meet this requirement. Before these companies can prune or remove trees, Seattle City Light must first prune the trees to minimize or eliminate the risk of branches falling into the lines. This is for your safety.
The power lines that run from pole-to-pole carry high-voltage electricity. Each year, a number of amateur tree pruners are seriously injured or killed when they come into contact with an energized line directly or indirectly through tools or tree limbs. Poles, ladders and elevated lifts can easily provide a dangerous electrical path if they make contact with an energized line. By pruning your own trees, you may be putting yourself in a dangerous position. We recommend that you hire a professional service and that you check with Seattle City Light before beginning. A list of arborists registered to work on Seattle Department of Transportation right-of-way property may be found at: www.seattle.gov/transportation/treecompanypermits.htm
How do I request wood chips?
Please do not plant vines, shrubs or trees directly adjacent to or on power poles or guy wires. Keep all vegetation at least 10 feet away from poles. Our crews must have quick access to climb poles when making repairs.
Depending on the species, young trees mature to different heights. When you select new trees, anticipate the height and spread of the mature tree in relation to power lines.
- Trees planted directly under or within 20 feet of the power lines should have a mature height less than 25 feet
- Trees that mature to 25 to 45 feet should be planted 20 to 50 feet away
- Trees greater than 45 feet at maturity should be planted more than 50 feet away
Smaller trees will remain healthier and look more natural without pruning. They will enhance your neighborhood environment while supporting a safe, reliable electrical service. We offer the Urban Tree Replacement Program to Seattle's neighborhoods. If you would like more information on this program, call (206) 386-1650.
City Light promotes the right tree in the right place. We offer a free publication, The Right Tree Book, with information on selecting and planting appropriate trees and shrubs around utility lines. To request a copy, call City Light at (206) 684-3000. Or you may print out a copy located at seattle.gov/light/vegetation-management
The Seattle Department of Transportation has information available about planting trees at www.seattle.gov/transportation/treeplanting.htm
How will I know if City Light is going to prune my tree?
You can request wood chips from Chip Drop at: https://www.chipdrop.in/login/
. This free service connects local tree care businesses with residents who want wood chips. Seattle City Light’s contracted tree trimmers utilize Chip Drop to find sites for their woodchips.
Before pruning work begins, a Seattle City Light representative will knock on the door of homes and buildings adjacent to the tree pruning area to give notice about the upcoming pruning work. If no one is there, they will leave a door hanger with tree pruning information and a contact phone number.
Can customers request that City Light prune trees?
During emergency conditions, if a tree has caused an outage or poses an imminent safety hazard, the work may be done immediately and the customer notified following the job.
For large projects, City Light will place a tree pruning notice in the local neighborhood newspaper and notify the district neighborhood council. A Utility representative will provide information at meetings upon request.
Yes, if you notice an urgent hazard such as a broken tree limb on a pole-to-pole power line or trees in the lines with arcing and sparking, please call (206)684-3000 and stay on the line to be connected to a customer service representative. To report non-emergency issues with trees in powerlines please call (206)386-1733, Monday-Friday between 8:00am and 4:00pm.
Under what circumstances can you enter my yard and prune my trees?
As an electrical utility, we are responsible for maintaining our system and to protect the health, safety and general welfare of the public. Customers must allow access to their property at reasonable hours to inspect, maintain, and repair the electrical system. We will notify you at least one week before coming onto your property unless there is an immediate and present emergency involving a tree on your property.
Who do I contact if I have tree pruning questions or issues?
What is the difference between transmission and distribution power lines?
Transmission lines carry higher voltages over longer distances. Our transmission lines carry 115kV and 230kV. Our Distribution system carries lower voltages shorter distances. Our distribution lines are 26kV, 14kV, and 4kV.
How does Seattle City Light help to ensure the health of trees and our urban forest?
We prune trees according to the International Society of Arboriculture’s Best Management Practices for Utility Pruning