Friday, August 29, 2008
Tree Trimming Around Power Lines Print E-mail

You may have noticed more activity in your neighborhood regarding tree trimming and vegetation maintenance.  Tree trimming around power lines has become a major focus for the City of Forest Grove Light and Power Department.  Trees growing into or near power lines can create safety and service reliability risks.  Close growing branches can provide access for children and others to contact high-voltage lines, with potential for serious injury or death. Branches touching power lines can spark and start fires.  On a wet rainy day, branches touching exposed power lines can cause the saturated tree to act as a conductor of electricity.  Tree limbs falling onto the lines during storms is the main reason for outages on any electric utility’s system.

           In the City of Forest Grove, mature trees are a wonderful asset to this community. These mature trees do bring the challenge to the municipal utility of maintaining clearances and maintaining the health of the tree.  The Light and Power Department employs Journeyman Tree-Trimmers who have obtained line-clearance tree trimming training through a three-year State apprenticeship program.  This program teaches directional pruning methods which are endorsed by the International Society of Arboriculture.  Rather than cutting all the limbs back to unsightly and unnatural stubs, branches are pruned back to the center of the trunk where trees normally shed them.  Future tree growth is directed away from the power lines. Directionally pruned trees are less susceptible to disease and insects and the overall structure of the tree is stronger and more resistant to high winds.  With mature trees, this isn’t as simple since these branches are usually the size of the trunk itself, and removing the branch will leave the tree permanently damaged and ultimately unhealthy.  Knowing this, the tree trimmers will recommend that the tree be replaced through our tree replacement program.

            Light and Power is a Tree Line USA utility.  What does this mean?  The Tree Line USA award is given to utilities that meet three requirements:  1) quality tree care, 2) annual worker training, and 3) tree planting with public education.  Light and Power has been a Tree Line USA award recipient for 7 years.  Part of our tree trimming program includes tree replacement.  Trees that must be removed due to our line clearance trimming are replaced by the utility at no cost to the property owner.  We provide a list of appropriate trees to be planted beneath the power lines that our customers can choose from.  This list is valuable even when planning your initial landscaping project.

            Due to State and Federal regulations which include the Public Utility Commission (PUC), the utility is required to trim trees back to 10 feet of the high voltage lines, even if the trees are on private property.  Depending on the type of tree and whether it is a fast or slow grower, we will trim back further in anticipation of the growth rate of the tree.  Some trees can grow back 10 feet in one year.  We will initially notify our customers when we will be trimming trees on private property and do our best to communicate the pruning options to get the best results.  If you have any questions regarding our tree trimming program, please feel free to give us a call at (503)992-3252.