The ANSI A-300 Part 1: Tree, Shrub and Other Woody Plant Maintenance—Standard Practices, Pruning are the accepted guidelines and are endorsed by the International Society of Arboriculture (ISA). They promote directional pruning methods which minimize pruning stress and focus on tree health while obtaining necessary clearance from power lines.
Only qualified utility line clearance professional arborists who meet OSHA qualifications are legally permitted to work within 10 feet of power lines or work on a tree that has branches within 10 feet of power lines. Line clearance arborists are trained to prune trees according to American National Standards Institute (ANSI) A-300 pruning standards and […]
In remote/rural locations, utilities often utilize mechanical equipment to increase efficiency and worker safety. Large saws mounted on high-reaching booms can be used to prune the sides of right-of-way corridors. In some cases, saws are suspended from helicopters. When using this equipment it is understood that the quality of the cuts can be less than […]
Situations where tree removal may be preferable to line clearance pruning include: Tall or fast-growing species growing directly under the power lines that require frequent pruning and will never have a natural form Saplings (brush) with the potential to grow into or close to the lines Large, previously topped trees under the lines Trees with […]
Undergrounding of lines is very expensive and results in more difficult (and longer) repairs in the event of a power failure. Also, converting an overhead system to underground typically causes substantial damage to existing trees’ root systems.
Directional pruning removes branches growing toward the power lines while leaving those that are growing away. It is the most appropriate pruning method for utility line clearance. How will a tree look after it is directionally pruned? Trees growing directly under power lines may appear U or V-shaped (crown reduction or throughpruning). Trees growing alongside […]
Utility companies are proactive and try to prune trees BEFORE they pose a risk to the power lines. Because trees are dynamic, factors such as swaying in the wind, sagging with ice/snow weight, and uprooting in storms are examples of how problems can develop without warning even if the trees are not in contact with […]
Typically, a qualified utility forester or vegetation manager prescribes the amount and type of pruning necessary based on: tree growth rate and structure wind direction tree species: strong or weak wooded tree health or vigor environmental factors water sources proximity of tree to wires and line configuration— higher voltage lines require greater clearance
It’s a matter of safety and providing reliable power for the members we serve. SAFETY—Utility vegetation maintenance reduces electric hazard risk to the public by: providing separation between wires and vegetation to eliminate potential electrical shock reducing potential wildfire hazards from tree/wire conflicts RELIABILITY—Trees are among the most common causes of utility service interruptions. Trees […]