Vegetation Management

Trees and branches that contact power lines is the leading cause of power outages on our system. Outages are always inconvenient. That is why we do everything we can to recognize our appreciation for trees while we meet our obligation to provide safe, reliable electric service. Through our tree trimming schedule, we direct tree growth away from power lines so we can limit any electric system damage that could be caused by extreme weather conditions. If a tree’s proximity to power lines is a threat to our electric system, our tree crew will trim the growth away from our equipment. These standards are guidelines for vegetation management, but their application may vary depending on the situation.


  • This standard covers the District’s requirements for maintenance near our energized facilities to provide clearance on all distribution lines operated by Skamania PUD.


  • The term ‘Maintenance’ is intended to encompass tree, brush and vegetation cutting, pruning, removal, disposal and control on rights of way utilized by the District.


  • To improve the reliability of Skamania PUD distribution systems by preventing outages from vegetation located on energized distribution facilities and minimizing outages from vegetation located adjacent to rights of way.
  • These facilities may be located in rights of way, easement areas, licensed areas, or district property. Use of the term “right of way” refers to all these areas.

Vegetation Control Options

  • This may include chemical, manual, or mechanical techniques.
  • The choice of control option(s) is based on effectiveness, environmental impact, site characteristics, worker and public health and safety concerns.

Typical Vegetation Clearance

  • A typical Skamania PUD vegetation clearance area is a minimum of 30 feet in total width, with the conductor in the center.
  • Electric right of way maintenance shall include adequate clearance of all active overhead utilities utilizing the right of way, including clearing vegetation from poles and guys.

Clearing Distance

  • Skamania PUD controls vegetation and maintains clearances on energized distribution facilities to achieve maintenance free periods or cycles.
  • We remove select danger trees that could potentially grow, fall or bend into the lines.
  • The selection of danger tree removals is based upon the overall condition of the tree, the stability of the ground around the tree, the tree species and any other defects that would cause the tree to be unstable and more likely to fall into the lines.
  • If a tree is healthy and stable, it is usually not designated for removal.
  • All energized distribution facilities way must be cleared to a minimum of 10 feet from any energized conductor.
  • Only side and top pruning are permitted with a minimum clearance of 10 feet from the energized conductors.
  • All vegetation between the conductor and the ground shall be cleared to the ground out to at least 10 feet on each side of the conductor.
  • All overhanging limbs up to a minimum of 15 feet above the conductor must be removed unless there are special unsafe conditions that would prevent
    4 removal. The final decision concerning leaving overhanging limbs will rest solely with Skamania PUD.
  • Shrubs and groundcover shall be trimmed to a minimum of 4-foot circumference around all guy wires.

Specification for vegetation managementTree Trimming/ Brushing

All activities shall conform to the most current published ANSI A300 standards for tree care operations and Z133.1 safety standards for arborists.

Tree Removal Candidates include but not limited to:

  • Dead, dying, diseased, deformed and unstable trees which have a high probability of failing and contacting Skamania PUD lines.
  • Trees that are located at homes, parks, or other areas, which person may climb easily and contact primary conductors.
  • Volunteer trees which will eventually interfere with Skamania PUD lines.
  • Immature trees that are not presently interfering with Skamania PUD lines but could at their mature height.
  • Trees that require extensive drop-crotch trimming.

Tree Removal and Trimming Conditions included but not limited to:

  • Tree removal is preferred over tree trimming.
  • Danger trees (outside of the right of way) should be only removed if there is a threat of the tree or limbs falling and contacting Skamania PUD lines and require landowner permission when off right of way.
  • Tree stumps will be treated within 30 minutes of cutting with an approved herbicide.
  • Tree growth regulators will be applied in those areas where pruning may not provide necessary line clearance.
  • Young, interspaced trees with potential to grow into the power lines will be removed at ground line.
  • Low growing shrubs (blackberry bushes, vines, or deciduous trees) will be removed on all right of ways when possible; they must not exceed 1 foot in height.
  • All ground trimming and brushing must also be sprayed with an approved herbicide if weather conditions are applicable.
  • Trees will be trimmed to a minimum clearance of 10 feet. Limbs may be cut farther from the conductors to comply with later trim methods. No stubs shall be left.
  • Overhanging branches will be cut down by 10% to increase limb strength and accommodate snow load.
  • All limbs shall be trimmed back to a lateral point at a minimum distance of 10 feet from all Skamania PUD conductors.
  • Cuts shall be made back to the main stem or to a branch, which is at least one-third the diameter of the portion being removed. In no case shall deciduous tree limbs be stubbed off at the edge of the clearing limits. Wherever possible, all trimming cuts shall be made to direct future growth and sprouting away from Skamania PUD conductors.
  • Where practical, cuts should be primarily restricted to large diameter branches made well within the crown. Shaping using many cuts of small diameter branches in the outer crown must be avoided.
  • Vines growing on poles and wires shall be cut at ground level.
  • All trees directly below conductors, and all weak, diseased and dead limbs above the conductors shall be removed.

Dead Tree Removal

  • Dead trees or other vegetation beyond the right of way that would strike Skamania PUD lines when falling shall be removed.
  • Leaning trees beyond the right of way which would strike the line in falling and which would require topping if not removed, shall either be removed or topped.
  • Skamania PUD shall obtain landowner’s permission prior to cutting trees outside of the right of way, unless an emergency exists that would allow the District to legally remove a tree without permission.


  • All ground cut vegetation shall be sprayed with an approved herbicide.

Clearing of Wood Waste

  • Skamania PUD shall dispose or disperse of all wood and wood products resulting from the pruning and removal process.
  • Slash may be chipped and blown on the right of way. If chipping is not possible due to terrain or other circumstances, the slash will be lopped and scattered on the outer limits of the right of way so that access for Skamania PUD line crew will not be inhibited.

Fire Prevention

  • Skamania PUD shall abide by all Washington State Industrial Fire Precaution Level (IFPL) restrictions and always have hand tools and fire suppression resources at the worksite.
  • The worksite shall be actively monitored for any signs of sparks, smoke and fire throughout the day and prior to leaving the worksite each day following fire watch criteria laid out in the IFPL.


Job site activities shall be conducted in accordance with applicable Federal, State and Local requirements to include but not limited to the:

  • National Electric Safety Code
  • OSHA 29 CFR Parts 1910-1926
  • Washington State Department of Transportation Manual on Uniform Traffic Control Devices

Site Preservation

  • Care shall be taken to preserve the natural ground covers where possible.
  • Rivers, lakes, streams, natural draining areas, ponds, etc. shall not be disturbed.
  • All local, state and federal laws and regulations will be followed when performing work around fish spawning streams.

Customer Notification

Skamania PUD uses Door Hangers to communicate with customers regarding notification of Tree Trimming maintenance projects in their area.

  • Door Hangers will be posted in a conspicuous location of the affected property (Conspicuous locations would include front doorknobs, garage doorknobs, property gates, etc)
  • The Door Hanger must give a good faith estimate of the time frame in which the trimming or removal shall take place
  • The Door Hanger must tell the customer how the utility or the representative may be contacted and a brief description of the work to be performed

Tree Trimming Requests

  • Every year Skamania PUD received a high volume of tree trimming requests
  • Skamania PUD removes or trims trees for safety and system reliability
  • A number of requests were rejected because they did not meet the guidelines

Skamania PUD will trim or remove trees if:

  • Trees are in the 30 foot right of way
  • Trees are, or will negatively impact the power lines

Skamania PUD will not trim or remove trees if:

  • Trees are not affecting the power lines
  • Trees are leaning away from the power lines
  • Trees are over structures including homes, garages, outbuildings, campers, etc.
  • Trees are not accessible by Skamania PUD equipment

Submit a Request

If you would like to submit a request for tree trimming, you can:

  • Login into SmartHub, go to Contact Us then Submit and Inquiry
  • Call our office at (509) 427-5126 and speak to a Customer Service Representative