Chapter 19. Hydro Line Management

Hydro Line Management

Hydro line operations are a major maintenance practice in all municipalities that can have a large effect on its urban forests. Trees conduct electricity and therefore trees planted under or next to power lines must be regularly pruned, and some cases removed, to ensure public safety and to maintain hydro supply. When tree branches grow into or come in contact with hydro wires, they can cause fires, power outages and can become safety hazards. Tree roots can also interfere with buried power lines and equipment.

Some power authorities have guides and other online resources for site-specific plantings, intended to help property owners plant trees without interfering with hydro lines. Guides inform property owners of height limitations for trees within a range of distances of power lines, identify potential appropriate species, and recommend proper maintenance, pruning, or removal of trees to maintain clearance and prevent unsafe conditions. Power authorities may offer property owners discounted consultations with arborists and planting services.

Canadian online resources:

• BC Hydro: Planting near power lines
• Electrical Safety Authority (Ontario): Planting Under or Around Powerlines & Electrical Equipment (PDF)
• Hydro One: Caring For Your Property: Vegetation Management
• Hydro Ottawa: Planting trees
• Hydro Québec: What to do BEFORE planting a tree

Non-Canadian online resources:

• International Society for Arboriculture: Avoiding Tree & Utility Conflicts (PDF)
• Purdue University Forestry and Natural Resources: Trees and Electric Lines (PDF)