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Vegetation Management

Trees are good conductors of electricity – when they grow too close or fall into power lines, trees can cause public safety risks like contact with high voltage power lines, fire, and power outages. As a preventative measure, we clear trees and excessive vegetation around electrical structures and underneath lines.

In order for our employees to safely and easily inspect, maintain, and repair our electrical system, we also maintain the trees, brush, and other plants around Hydro facilities and plants. Vegetation growth can also prevent our crews from reaching and responding promptly to emergency situations and outages.

Our approach

Under Hydro’s Vegetation Management Plan, several methods are used to control vegetation in order to maintain the safety and reliability of our lines. Manual brush clearing and tree trimming are completed yearly around transmission lines. However, given the over 7,000 km of lines that must be maintained, as well as geographic and terrain challenges, this method must be combined with other vegetation control methods, including the selective application of herbicides. Selective herbicide usage offers long-term control of trees. Repeated cutting of hardwood species such as alder increases the stem density and root mass and only provides short term control. Selective herbicide, therefore, helps to greatly reduce potential power outages, fire hazards, and safety risks.

The goal of Hydro’s vegetation management program is to remove the vegetation that poses potential dangers (such as spruce, fir, juniper, birch, and alder) and promote the growth of low growing species such as grasses and berries.

Regulation and communication

The program is carefully regulated through Health Canada and the Pest Control Products Act. The use of herbicides is also regulated provincially through the Department of Environment and Conservation. There are specific guidelines and buffer zones.

Herbicide application is completed on average once every seven to ten years (different areas in the province are treated each year; 200-400 hectares each maintenance season). Hydro informs town councils and area residents when an area is being treated and we post signage around the power lines. The signs state that the area has been treated, the chemical common name, pesticide control registration number, and the date sprayed.

Products used are registered under the Pesticide Control Act to ensure the protection of human health and the environment.