Tree Trimming Information

Tree trimming crew at work

To provide SAFE and RELIABLE electricity service to our ratepayers, we seek to provide a minimum of 10' to 15’ (depends on line voltage and type of tree) clearance from overhead conductors.  In some cases, trees will be trimmed heavily.

Where feasible and necessary, we will seek to remove fast growing or hazardous trees from under powerlines. Tree removal candidates include the following:

  • Fast growing trees that interfere with primary conductors.

  • Deciduous trees that require excessive trimming.

  • Dead, dying, diseased or defective trees which have a high probability of falling and contacting primary conductors.

  • Trees with tree houses or climbable trees in close proximity to transmission or primary conductors at or near homes, schools, parks or any other locations where people frequently visit.

  • Naturally seeded trees or smaller trees that will eventually interfere with primary conductors.

Considering these conditions, trimming these trees and allowing them to remain within the ROW or in hazard areas under/adjacent to overhead conductors is not cost effective. The utility will make site specific decisions regarding the treatment or removal of these trees. Trees that are determined to be defective or damaged under these guidelines are candidates for removal under PUD trimming/removal guidelines.

No trees will be removed without written landowner permission.

Only customers who have trees removed by the Asplundh crews or PUD crews qualify for our Tree Replacement Program.  (See Replacement Program details here.)

The PUD will make a responsible effort to notify the landowner if their trees will require trimming with large V-trim or side trim cuts. The PUD does reserve the right to trim these trees if they pose a hazard to overhead conductors.

All wood will be removed from the site unless otherwise specified by the owner.

Asplundh Tree Experts use modern arboriculture methods to trim trees.  They include:

  • Techniques consistent with practice of natural, lateral and drop crotch trimming shall be utilized

  • Cuts are made back to a main stem or branch of sufficient size.

  • All trimming cuts shall me made to direct future growth sprouting away from conductors.

  • Conifers should be trimmed in a manner that allows them to retain as much of their natural shape as possible.

  • All dead branches overhanging primary conductors at any height shall be removed.

  • Where practical, cuts should be primarily restricted to large diameter branches made well within the crown.

  • Remove living branches by making cuts as close as possible to the branch collar. Remove dead branches by making cuts as close as possible to the living tissue remaining at the base of the branch.

  • Avoid stripping or tearing of bark when cutting large limbs.

Specific Cuts / Methods are as follows:

Directional Pruning - Prune trees to eliminate branches that will grow toward and into power lines, leaving behind select branches that grow away from power lines.  The branch collar is left intact.  All trimming cuts shall be made to direct future growth and sprouting away from conductors; maintaining the health of the tree while establishing acceptable clearance between lines and branches.

Collar cut – cutting of the limb just beyond the point of intersection with the trunk of the tree or another limb at the branch collar. When properly made, it will allow the trees protective zone to aid in closing the wound. Topping, flush cuts or branch tipping shall not be practiced. Lateral limbs that are left will be at least one-third the size of the limb being cut.

These trees need trimming!

Drop-Crotch Trimming – a technique that removes a limb back to another limb or the trees stem within the crown. The goal is to thin unwanted growth. Minimal drop-crotch trimming should be practiced on deciduous trees that are subject to excessive or rapid regrowth or sun scald. When trimming conifers to the side of facilities, limbs should be cut back to the stem instead of tipping the ends of the branches.

Incorrect Methods - Shaping and Pollarding. Shaping refers to the incorrect action of pruning or tipping a tree and its branches for aesthetic or ornamental appeal only. Shaped trees re-grow quickly with vertical suckers that sprout from cut ends. The suckers are only weakly attached to the branches. This practice has been determined detrimental to overall tree health. Pollarding is the practice of pruning trees annually to remove all new growth creating an unnatural affect.

For questions or comments on any of our Right of Way Clearance and Tree Trimming Programs please contact Right-of-Way Superintendent Nick Christoph at 509-422-8435 or email