Transmission Lines & Trees FAQ

Transmission lines are only insulated by air. They require regular maintenance of surrounding vegetation to sustain minimum clearances of obstructions. OPPD’s vegetation management program ensures the transmission system meets company, industry and federal standards to ensure the safe and reliable delivery of electricity to customers, while also providing access to maintain facilities.

OPPD has modified its standards along with the industry over the last decade. Several widespread outages, including one in the northeast affecting 50 million people in eight states and portions of Canada, have forced the industry to take a more conservative approach related to transmission corridor maintenance. Utilities operating high-voltage transmission lines are required to establish and follow a vegetation management program that eliminates all threats to safety and reliability of high-voltage transmission lines.

In the past, it was not uncommon for utilities to allow certain trees and vegetation in transmission corridors as well as trimming and pruning rather than tree removal. This approach has repeatedly proven to be ineffective in the utility industry in preventing outages, arcing, and fire and shock hazards.

Yes, OPPD will trim or remove a tree if it is structurally weakened, is considered a fast-growing or soft-wooded species, or if it poses a danger to the integrity of the transmission line. A danger tree is defined as any tree located inside or outside the right-of-way that would fall within 15 feet of a power line or within 5 feet of a transmission structure. Most easements grant OPPD the right to trim or remove such trees for the protection of the transmission line and the safety and reliability of the transmission system.

Yes. OPPD owns the right within its transmission corridors to trim or remove all trees and brush to safely and efficiency survey, construct, reconstruct, relocate, inspect, repair, replace, maintain, operate and remove transmission lines. Within the area (called an easement), OPPD also has the right to trim or remove trees that could potentially fall within 15 feet of the nearest power line.

Transmission corridor widths range from 50 to 200 feet depending on the size and voltage of the power line. The higher the voltage of the power line, the more clearance required. Electricity traveling through these lines will look for the most direct path to the ground by jumping or arcing to nearby objects including a tall-growing tree. To avoid this, we maintain a safe distance between power lines and tree limbs. 

A clear zone is maintained on all sides and below power lines to maintain a safe distance between anything that can conduct electricity. Allowances must also be made for line sag, wind and weather conditions. A heavy electrical load on a very hot day will heat-up and stretch power lines causing them to sag. Because the amount of sag varies, a safe clearance in winter may not provide the same safety on a summer day. Additional hazards include heavy winds that can blow branches into power lines and extra weight from snow and ice that bend or break branches causing a potential flashover. 

Most trees should not be planted directly underneath a transmission power line, especially extra high voltage lines. OPPD may approve selected low-growing vegetation at carefully chosen locations provided it does not impact reliable and safe operations. Contact OPPD’s Real Property and Land Management team by calling our hotline at 531-226-3062 or emailing landmanagement@oppd.com for a consultation. Remember, vegetation located within or along the immediate edge of the corridor is planted at your own risk.

Yes. OPPD uses qualified contractors to apply herbicides that are approved and labeled by the Environmental Protection Agency. The use of herbicides allows for selective removal of undesirable vegetation with minimal impact to the surrounding environment while extending the time interval between more invasive practices such as mowing. Maintaining rights-of-way with the use of herbicides frequently results in more ecologically diverse, healthy and aesthetically pleasing corridors than those maintained only by mechanical means.

No, OPPD's easement allows access to private property to construct, reconstruct, operate, maintain, and patrol transmission lines.

An OPPD representative will make every attempt to notify you of work that needs to be completed. However, it may be necessary to perform emergency trimming or removal without prior notification to eliminate potential tree-power line hazards.

Yes. OPPD has the right to require the removal of decks, garages, sheds and other structures that have been built without prior approval.

Reach out to the OPPD Real Property and Land Management team by calling our hotline at 531-226-3062 or emailing landmanagement@oppd.com. You can also go through our formal approval process to change the grade within a corridor or obtain approval for a specific obstruction. When a request is made, OPPD analyzes the safety and reliability risks of the request.

Yes. Deer stands should be located in the outer edge of the right-of-way and must not exceed 15 feet in height. Do not attach deer stands to power poles or under power lines.