Manitoba Maple Dangers

In this post, we will go over the hazards and potential risks the Manitoba Maple tree possesses.

Brendan O'Brien

4/1/20242 min read

Understanding the Risks of Manitoba Maple Trees in Ontario: Why They're Unsafe and What You Need to Know

Manitoba Maple trees (Acer negundo), also known as Box Elder trees, are a common sight in many landscapes across Ontario. While these fast-growing trees offer shade and aesthetic appeal, they also present significant risks to both property and safety. In this guide, we'll explore why Manitoba Maple trees are considered unsafe in Ontario and the potential hazards associated with having them on your property.

1. Weak Wood Structure:

One of the primary reasons Manitoba Maple trees are deemed unsafe is their weak wood structure. Unlike some other tree species, Manitoba Maple trees have brittle wood that is prone to breakage, especially during severe weather events such as high winds, storms, or heavy snowfall. This can result in falling branches or entire tree limbs, posing a risk to people, property, and vehicles below.

2. Invasive Roots:

Manitoba Maple trees are known for their aggressive root systems, which can cause significant damage to underground utilities, foundations, sidewalks, and driveways. The expansive root network of these trees seeks out moisture and can invade sewer lines, causing blockages and costly repairs. In urban environments where space is limited, the invasive roots of Manitoba Maple trees can create maintenance headaches and safety hazards.

3. Susceptibility to Disease and Pests:

Manitoba Maple trees are susceptible to various diseases and pests that can weaken their overall health and structural integrity. Common issues include verticillium wilt, powdery mildew, cankers, and infestations by insects such as aphids and scale insects. Diseased or infested Manitoba Maple trees are more prone to branch dieback, decay, and structural failure, increasing the risk of falling debris and potential hazards.

4. Rapid Growth and Weak Branch Attachments:

Manitoba Maple trees are known for their rapid growth rate, which can lead to weak branch attachments and structural imbalances. Poorly attached branches are more likely to break under the weight of foliage, ice, or snow, posing a risk to anyone or anything below. Regular pruning and maintenance are essential to reduce the risk of branch failure, but even with proper care, Manitoba Maple trees may remain prone to structural issues.


While Manitoba Maple trees may provide shade and aesthetic value, their inherent risks make them unsuitable choices for many urban and suburban environments in Ontario. Homeowners considering planting or maintaining Manitoba Maple trees should weigh the potential hazards against the benefits and explore alternative tree species that offer similar benefits without the associated risks.

If you have Manitoba Maple trees on your property and are concerned about their safety or health, consult with a certified arborist or tree care professional. They can assess the condition of your trees, recommend appropriate actions, and help you mitigate potential risks to ensure the safety of your property and surroundings.