They're eye-pleasing and environmentally positive. But in a storm, trees can play havoc with streets, communication and power lines.
That's a lesson Americans on the Atlantic coast learned recently, as tropical storm Sandy sent fierce winds through their neighbourhoods.
But wind can be an everyday thing in Lethbridge, and officials say the city's trees are proactively trimmed for safety.
City-owned trees in boulevards and parks are pruned to keep them away from overhead wires, explains Brent Smith, a technician with the city's electric utility.
And city residents can have their fence-line trees trimmed as well, if they potentially threaten power distribution lines running down their back lanes.
Parks staff are responsible for shrubs and trees in the city's green spaces, but Smith says the electric system hires qualified contractors to trim trees that could affect residents' power supply.
"Most of our overhead is down the back lanes," in the city's southside and northside neighbourhoods at least.
It's designed to withstand Lethbridge winds, Smith points out. But problems can develop when heavy snowfall weighs down upper branches, putting them in conflict with power lines.
By trimming trees on a scheduled basis, he explains, the city has all but avoided those outages in recent years.
To protect the electrical system, that's done on a rotating three-year basis.
"It's really not an issue anymore," he reports. "We hire qualified utility arborists."
West of the river, Smith says, most of the residential services are installed underground. But trees can still become a problem.
"On the west, it's more the roots we're concerned with, not the branches."
When homeowners' trees conflict with an overhead power line (or phone line) over their property, Smith says it's up to them to hire a tree maintenance company - or tackle the job themselves.
"The service wire to their home is their responsibility."
When it's your neighbour's tree that's spreading past the property line, he says, it may be possible to work something out with its owner if your power line is in danger.
At the back fence-line, meanwhile, Smith says an owner can ask to have tall trees trimmed if they're close to a power service - and accessible by "bucket" from the back lane. If trees are too close to a transformer or other pole-mounted equipment, he says electrical crews will handle the job instead of arborists.
Sometimes, he adds, that may mean switching off a local circuit for a few minutes. If that's required, affected residents are notified.
If worse comes to worst, with a branch or tree knocking down someone's service line, Smith says electrical crews are always on call.
But depending on the time of day, it could be four hours or longer before the snapped line is replaced.