Wind in Toronto is more than a fleeting weather condition—it’s a natural force that shapes our urban forest and poses significant challenges for trees. When high winds strike, they can break branches, split trunks, and even uproot trees. This can mean getting emergency tree care such as tree pruning or tree removal.

For homeowners, understanding the relationship between wind and trees is critical for safeguarding your property and preserving your trees.

The Unique Wind Conditions of Toronto

Toronto’s geography and climate create unique wind patterns that frequently impact urban trees, especially with high winds. The city’s proximity to Lake Ontario, dense urban layout, and changing seasonal weather all contribute to complex wind dynamics.

Common Types of Wind Events in Toronto

  1. Lake Breezes
    Toronto’s location on Lake Ontario leads to lake breezes caused by temperature differences between land and water. While often mild, these breezes can strengthen during certain conditions, creating localized high winds that stress trees.
  2. Southwesterly Winds
    Frequently experienced in Toronto, southwesterly winds are driven by strong pressure gradients over the Great Lakes. Strong winds and gusts up to 80–90 km/h can occur, often resulting in broken branches, damaged canopies, and uprooted trees.
  3. Straight-Line Winds
    Unlike swirling tornado winds, straight-line winds are intense, unidirectional gusts often caused by downdrafts from thunderstorms. These strong winds can hit urban trees suddenly and forcefully, leading to snapped branches and leaning trees.
  4. Derechos
    While rare, derechos—long-lasting, powerful windstorms caused by thunderstorm systems—are not unknown in Toronto. The May 2022 derecho brought widespread destruction, downing thousands of trees across southern Ontario.

oak tree cracked in half after high winds in Toronto

How High Winds Damage Trees

When winds reach speeds of 70–90 km/h, the risk of tree damage rises significantly. Trees respond to wind based on their structure, health, and environment, but urban conditions exacerbate vulnerabilities. Here’s how strong winds impacts trees:

Broken Branches

High winds strain branches, especially those with weak attachments, dense canopies, or deadwood. Norway maples, a common Toronto tree, are particularly prone to breakage due to their heavy canopies.

Preventing Broken Branches: Pruning dense trees reduces wind resistance, minimizing the risk of branch breakage.

Splintered Trunks

Gusts from high winds can crack or split tree trunks, particularly in species with structural weaknesses like silver maples.

Preventative Tree Care for Cracks: Proper structural pruning and cabling are key to supporting trees with vulnerable trunks.

Uprooted Trees

Shallow-rooted trees, such as birches, are at greater risk of uprooting in compacted urban soils. Uprooted or downed trees are very dangerous. Strong winds, combined with Toronto’s constrained planting spaces, can destabilize trees.

Preventing Tree Uprooting: Root zone care, including aeration and mulching, along with crown thinning, can improve a tree’s stability.

Hanging Limbs

Windstorms often leave damaged limbs hanging precariously, posing immediate risks to safety. Hanging branches should only be removed by a certified arborist to avoid injury and further damage.

Preventing Hangers: Look up! Then, call an arborist to remove them. Be sure to stay back from broken or dead limbs.

Why Urban Trees Are More Vulnerable to Wind

Unlike trees in forests, urban trees face unique challenges that make them more susceptible to wind damage. Here’s why:

1. Over-pruning and Improper Maintenance

Urban trees are frequently overpruned, often for aesthetic reasons or utility clearance. Overpruning like tree topping can weaken trees by removing too many branches at once, creating dense, weak regrowth prone to breakage. Certified arborists can help balance pruning needs while maintaining structural integrity.

2. Exposure to Urban Winds

Toronto’s tall buildings and open streets create wind tunnels, amplifying wind speeds at ground level. This “urban canyon effect” intensifies pressure on street and yard trees, particularly in areas like downtown Toronto and neighborhoods near the waterfront.

3. Isolation in City vs. Support in Forests

In forests, trees grow together, forming natural windbreaks and sharing structural loads. Urban trees often bear the full force of wind on their own, making them more likely to suffer damage. Trees in urban environments develop more “reaction wood” (think super slow growing muscles) in response to wind, which makes them more rigid than forest trees and at great risk of breakage.

4. Compacted Soils and Restricted Root Zones

Toronto’s urban trees often grow in compacted soils, limiting root expansion and reducing stability. Planting areas like boulevards, small yards, or hardscaped spaces (patio, driveway) restrict root development, leaving Toronto trees more vulnerable to uprooting during storms.

Spruce tree fell over and hit neighbour house in Kingsway area, Etobicoke. Tree leaning against house and shed, being cut and removed by Certified Arborists after high winds in storm.

Proactive Tree Care for Wind Resilience

Proper tree care can reduce the risk of wind damage and protect your property. Here’s what you can do:

1. Pruning for Wind Resistance

Strategic pruning, especially for species like Norway maples and cedars, reduces canopy density and improves airflow. This helps trees better withstand strong gusts. This includes crown thinning, crown reduction and other types of pruning to increase wind flow in the canopy. 

Pro-tip: This sounds easy, but in reality pruning for “wind sail” or wind effect is quite complex because trees also use their branches to sway, dissipating the force of wind. Too much wind may overwhelm the tree, but too much pruning may make it weaker. Always ensure arborists performing this service have the right training, education and credentials.

2. Cabling and Bracing

Trees with weak or damaged trunks and branches can benefit from cabling or bracing. These supports provide additional stability and prevent further damage during wind events.

Pro-tip: Cabling and bracing can change the movement dynamics of trees in both regular and high wind situations. It should only be implemented when essential, as it is a permanent installation that requires ongoing monitoring and maintenance.

3. Root Zone Care

Mulching and aeration improve soil quality, allowing roots to anchor more effectively. For trees in compacted soils, these steps are essential to increase resilience.

Pro-tip: If you’ve got a large tree at the edge of a driveway, patio, house or are planning landscaping (installing pavers, stones, turf or cement), consult with an arborist to do a risk assessment.

4. Tree Health Assessments

A certified arborist can inspect your trees for vulnerabilities, such as cracks, decay, or leaning, and recommend solutions to prevent future damage. 

Pro-tip: Ensure you hire someone with tree risk assessment credentials and expertise in risk mitigation. Knowing how to apply tree science and assess risk is a specialized area of arboriculture that involves addition education and training beyond tree cutting, climbing etc.

5. Choosing the Right Trees

When planting new trees, consider species better suited to Toronto’s urban environment and high-wind risks. Trees with strong wood and deep roots, like oaks and honey locusts, are excellent choices for wind resistance.

Understanding Toronto’s Climate and the Future of Wind Events

Toronto is experiencing more frequent high-wind events due to climate change. Warmer temperatures and shifting weather patterns are intensifying storms, increasing the likelihood of damage to trees and property. According to the Government of Canada Climate Data, wind gusts exceeding 70–90 km/h are expected to become more common in southern Ontario.

When to Call an Arborist

Not all tree damage is immediately obvious after a wind event. Homeowners should contact a certified arborist if:

  • Limbs are hanging or broken after a storm.
  • Trees are leaning or show signs of root heaving.
  • Large cracks or splits are visible in the trunk or branches.
  • You want to assess and prepare your trees for future high-wind events.

A certified arborist will evaluate your tree’s condition and recommend appropriate care, such as pruning, cabling, or root zone treatments, to improve stability and resilience.

Protecting Toronto’s Urban Forest One Tree at a Time

Toronto’s trees are an essential part of the city’s landscape, providing shade, beauty, and environmental benefits. By understanding the risks of wind damage and taking proactive steps to care for your trees, you can protect both your property and the broader urban canopy.

For expert advice, assessments, and tree care tailored to Toronto’s unique conditions, contact Vista Tree Management today. Let’s work together to keep Toronto’s trees thriving, even in the face of strong winds.