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Tree pruning and removals vital to power outage prevention

Vegetation crew using a truck to maintain trees close to power lines.
Certified Utility Arborists from one of our contractors prune trees alongside a distribution power line near Highway 37 North, about a three-hour drive north of Terrace.

Our vegetation team works with expert arborists to remove potential hazards

For our vegetation management crews, the preparation for the next big storm happens year-round.

In a province blessed with some of the tallest and fastest growing trees in North America, ensuring they don't fall on power lines is a massive task.

Over half of all outages in the province are caused by adverse weather causing trees and vegetation to come into contact with our system. Our in-house vegetation experts manage vegetation in an environmentally, socially and financially sustainable way, while keeping the electrical system safe and reliable. They work with Certified Utility Arborists who are qualified to work in close proximity to energized power lines.

"We're non-stop," says Elaine Sanchez, a distribution vegetation coordinator working out of Terrace. "Through maintenance contracts, we hire Certified Utility Arborists to remove hazard trees and remove the smaller brush that grows underneath power lines. We try to use more mechanical tools because it speeds up the process, but there are a lot of riparian areas [wetlands and areas near water] where you have to be very selective – you can't just cut things down or take a mower through. You have to do some things by hand."

Trees and plants that grow too close to our power lines can lead to power outages, fires, wildfires, and safety risks. That's why we constantly monitor and maintain vegetation near our power lines. After a multi-year drought in in B.C., we're also tending to drought-weakened trees and encouraging customers to be prepared for weather-related power outages as storm season begins.

A vegetation coordinator's job is dynamic with a lot of variety. They have customer touchpoints and relationships with contractors and municipalities. They become experts in different tree and vegetation species growing throughout their regions and how fast each species grows, then plan work in three- to four-year cycles.

The actual vegetation work (mowing, cutting, pruning, removals) is done by contractors who hire Certified Utility Arborists. Trees are only removed when necessary, and only after careful consideration.

Search on a B.C. careers site and you'll see job postings for both BC Hydro vegetation coordinators and for Certified Utility Arborists, including apprentice positions. Sanchez says It's challenging but rewarding work.

"These contractors are working through all types of weather, working long hours," she says. "They have a job to do – it's about protecting the homeowner by keeping that power line safe and secure."

Regardless of our best efforts, power outages still happen. Make sure you have an emergency kit and are prepared for an outage.

Vegetation crew using a rake chipper.
Following pruning of trees along a distribution line along Highway 97 north of Terrace, workers rake debris off the forest floor to load it into a chipper.

Trees are closer to power lines than you may think

Vegetation crews work along distribution power lines, both along highways and inside neighbourhoods. They mow, prune trees, and sometimes remove hazard trees. Along roadways, they ensure branches are a minimum of five metres clear of power lines.

If you think that much clearance looks like overkill, think again.

Sanchez says that in these times of drought, more trees at the edges of rights of way are dying. They tend to be more exposed to weather extremes because they're not protected within the forest. And the effects of wind and snow factor heavily into assessing whether even a healthy tree is at least five metres clear of power lines.

"When the winds come, especially during the winter storm season, those branches and those trees are moving, so we have to compensate for that," she says. "If you were to just drive by on a typical day, you might see a nice, big, wide open clearance. But come storm season, you're getting trees that are moving in the wind, or weighed down by snow."

In some areas of B.C., vegetation crews are literally in a race to get pruning and clearing done before the snow falls. Sanchez says that because her area is largely coastal, temperatures are milder and work can be done into the winter months. But winter hits harder in the B.C. interior, with heavy snowfall and freezing temperatures making work difficult or impossible.

"When it gets below -20° C, crews aren't going out because the hydraulics [in mechanical equipment] just don't work," she says. "And you're not going to send a mower out in two feet of snow. So at this time of year, we're really trying to finish up all our essential work, a last push to get all the pruning and removals of hazard trees completed."

A few ways homeowners can help

It's a homeowners' responsibility to maintain the trees and vegetation around the service wire (the line that carries electricity from the pole to your home) and underground wires to transformer boxes near your property. The height of trees and vegetation in this area should be at least one metre below the service wire, and shrubs and plants near transformer boxes must have three metres clearance on all sides.

Keep in mind that trees are much more than what you see overhead. In many instances, the root area of a tree is larger than the branch spread above ground. Trees planted near underground lines could have their roots damaged if the lines need to be dug up for repairs, and the biggest danger to underground lines occurs during planting.

Before you plant, make sure that you're aware of the location of any underground utilities. Never assume that these utility lines are buried deeper than you plan to dig. Use the free BC 1 Call service to submit a request for a report on which underground services – including wires, water and gas lines – are on your property and where they're located.

You should also be aware for signs that a tree on your property is damaged and weakened.

"Look at the trees every year," says Sanchez. "Are there dead branches? Are there hanging limbs, or recent cracks in the tree trunk due to freezing and thawing? Those cracks will only get larger and worse over time. Do you see mushrooms or funguses growing at the base or on the trunk of the tree?

"Once you start looking at the trees a little bit closer, you might see that a tree isn't doing that well. And maybe it's time to get a proper assessment to check for disease and overall tree health. This isn't just about protecting our power lines, but also the dwellings and infrastructure within the property. Trees are heavy and they can do a lot of damage when they fall down."

Rather than pruning a damaged tree, consider that removing it may be preferable. You may find your city or municipality offers vouchers to save on the cost of tree purchases.

Here are a few other ways homeowners can help maintain safety around power lines in neighbourhoods:

  • Plant the right tree in the right place: Use our trees and plants guide to help select the right trees for near power lines or transformer boxes on your property.
  • Trim and prune trees and shrubs regularly: Prune trees and shrubs to keep them outside of the recommendation zones. You can do your own pruning as long as you keep yourself, the tools you're using and all parts of the tree at least three metres (10 feet) away from distribution power lines. If you can't or are unsure of the voltage, contact a Certified Utility Arborist (CUA) to prune your trees.
  • Consider a plant's roots: Consider the root systems of the plants you select as these can interfere with the cables buried beneath a transformer or underground power lines.
  • Opt for native and drought-tolerant species: Know which climate zone you're in, and be aware how watering restrictions might impact the trees and plants on your property.
  • Clear the ground of dead branches and leaves: Particularly if you live alongside a forest, prune off dead limbs and clear the forest floor of dead wood and other flammable debris to help prevent wildfires.

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