Clearances for Trees

When trees, shrubs or vines are too close to the Overhead (OH) electrical infrastructure, there are potential hazards from branches and limbs such as fires, power outages, or direct contact when playing in or working around hidden lines.

Trees, shrubs, and vines should not be placed closer than 3 m (10 ft) from the base of an electrical pole, and as per Figure 1.

When selecting trees for planting, it is important to consider that different varieties grow at different rates and those that grow faster will need to be trimmed more often, or be planted farther from OH electrical infrastructure.

As shown in Figure 1, the following tree planting zones apply:

  • Low Zone – Trees and shrubs planted under the electrical lines should have a maximum mature height and spread of 4.5 m (15 ft).
  • Medium Zone – The maximum mature height and spread of trees planted from the outer edge of the Low Zone in all directions, measuring 7.6 m (25 ft) from OH lines.
  • Tall Zone – Extends from the outer edge of the Medium Zone, and measures 7.6 m (25 ft) from the OH lines. At maturity, trees planted in this zone should not encroach on the Medium Zone.

Tree Trimming

A tree that grows too close to the OH electrical lines will need to maintain a safe clearance of 3 m (10 ft). Tree trimming near power infrastructure must be completed by qualified utility arborists.

Should any property owner need to do work near the OH electrical infrastructure and these distances cannot be met, they should contact Niagara-on-the-Lake Hydro to discuss solutions.

Underground Clearance

When planting in the vicinity of Underground (UG) electrical infrastructure, the minimum clearance required from the edge of the root ball to the edge of the UG cables is 1 m (3 ft).  This protects the electrical infrastructure, and reduces damage to the roots of the trees should Niagara-on-the-Lake Hydro need to access its equipment. If the minimum distance cannot be achieved, Niagara-on-the-Lake Hydro may require the installation of a root deflector against the root ball.


UG electrical infrastructure may be buried and can be at different depths. When planting a tree, a locate must be requested before digging.

Request a locate:

Ontario One Call



Tree planting and removal can involve deep excavation that has the potential to cause damage. The excavation method must protect the UG electrical infrastructure if within 1m (3 ft), i.e. hand, vacuum, or pneumatic tools, as approved by Niagara-on-the-Lake Hydro.