What Happens to Deciduous Trees in Winnipeg Winters?

Winter in Winnipeg is no joke, and while you’re bundling up in parkas and sipping hot cocoa, your deciduous trees are gearing up for their own battle with the elements.

These leafy giants don’t get a cozy coat or mittens. Yet, they survive winters that could make a polar bear shiver. How? By adapting to protect themselves from frostbite (yes, trees have their version of it).

Today, let’s talk about the incredible ways deciduous trees traverse their way through winter. We’ll also go through what you can do to keep them thriving through Winnipeg’s icy embrace!

The Science Behind Dormancy

Dormancy is a survival strategy that slows down the growth of trees, helping them conserve energy during the cold months when resources are scarce. It’s basically a version of hibernation. But, instead of hiding underground or in a cave somewhere, trees undergo fascinating biological changes to weather the extreme cold.

Trees are masters of sensing seasonal changes. As daylight hours grow shorter and temperatures dip, your trees get the message loud and clear: winter is coming.

This shift triggers a chain reaction in their cells, instructing them to prepare for dormancy. It’s a mix of plant intuition and nature’s genius.

One of the most noticeable things during this time is leaf shedding. As days get shorter, trees stop producing chlorophyll, the pigment that makes leaves green. Without chlorophyll, other pigments like yellows and reds emerge, giving us those stunning autumn displays. Eventually, trees shed their leaves entirely.

But, why shed leaves?

It’s all about water and energy conservation. Leaves are thirsty little things, and keeping them hydrated during a Winnipeg winter is impossible with frozen soil. By dropping their foliage, trees reduce water loss and focus their energy on keeping their core systems intact.

Trees aren’t simply "sleeping" through the winter. Their dormancy is a carefully orchestrated survival tactic, ensuring they’re ready to flourish again in spring.

How Deciduous Trees Adapt to Winnipeg Winters

Deciduous trees are master survivalists. While they may look lifeless with bare branches, these trees are busy behind the scenes, adapting to the extreme cold and fluctuating temperatures.

• Water Movement in Cells: To avoid their cells turning into popsicles, trees move water from inside the cells to the spaces between them. This prevents ice from forming within the cells, which could cause them to burst. Instead, the water outside freezes, releasing a small amount of heat that helps protect the tree.
• Production of Antifreeze Substances: Trees don’t need scarves or mittens because they produce their own “antifreeze.” Sugars, proteins, and fats accumulate inside the cells, lowering their freezing point. This means even in the most frigid temperatures, these hardy cells stay intact.
• Bark as a Shield: The bark isn’t just there to look rugged – it’s the insulating shield protecting the tree from the extreme cold. Thick bark helps trees resist extreme temperature drops by keeping the inner layers snug and warm. For some trees, the outer bark even reflects sunlight, reducing the risk of sudden freezing.
• Reduced Metabolic Activity: During dormancy, a tree’s metabolism slows down significantly. This helps conserve energy and resources, as the tree focuses solely on survival rather than growth. As is in dormancy, the tree is pausing its usual activities to stay warm.
• Root System Activity: While growth above ground halts, the roots often remain active, especially in the early winter. Roots can still absorb water and nutrients from the soil before it completely freezes. This is crucial in contributing to the tree’s survival during the harshest months.

Common Winter Challenges for Deciduous Trees

Winter in Winnipeg is a gruelling trial for deciduous trees. And while these trees have evolved to withstand harsh conditions, there are a few challenges that make winter especially tough.

• Frost Heaving: Winnipeg’s infamous freeze-thaw cycles can cause frost heaving, where the soil expands and contracts, pushing roots closer to the surface. This not only exposes roots to the harsh cold but also destabilizes the tree, making it more vulnerable to damage.
• Frost Cracks: Freeze-thaw cycles can also cause frost cracks—those long vertical splits you might see on tree trunks. These cracks can expose trees to pests and diseases. So, while they’re mostly an aesthetic issue, they’re not ideal for tree health either.
• Sunscald: Don’t let the winter sun fool you into thinking it’s good for your trees. Its warmth during the day can trick tree bark into "waking up." When temperatures drop again at night, the rapid freeze can cause the bark to crack. These unsightly fissures, often on the south or southwest side of the tree, leave it vulnerable to disease and pests.
• Heavy Snow and Ice: Winnipeg’s snowfalls are picturesque from the comfort of your home. But it’s much different for the trees. The weight of heavy snow or ice build-up can snap branches, especially on younger or more brittle trees. This can cause long-term structural damage, not to mention a mess in your yard.
• Winter Drought: Frozen ground means water is hard to come by, even when the tree desperately needs hydration. This is particularly challenging for deciduous trees, which may struggle to stay hydrated through the long winter months. Winter drought can lead to weakened trees come spring.

What You Can Do To Help

While trees are pretty self-sufficient, giving them a hand before winter can make a world of difference. Here’s how to help your deciduous trees handle Winnipeg’s winter-like pros.

Hydrate Before the Freeze

Trees need a solid drink before the ground freezes solid. Water deeply in fall to ensure the roots have enough moisture to last through winter. This is especially critical during dry autumns. Aim to soak the soil to a depth of about 12 inches, targeting the area beneath the canopy.

Add a Mulch Blanket

A thick layer of organic mulch acts as a blanket for the soil, protecting roots from extreme temperature fluctuations and frost heaving. Spread 4 inches of mulch around the tree’s crown dripline, keeping it a few inches away from the trunk to avoid rot. As a bonus, remember that mulch also retains moisture in the soil.

Prune for Structure and Safety

Late fall is the perfect time to prune weak or dead branches, especially those that might snap under heavy snow or ice. Focus on creating a balanced structure to reduce stress on the tree during winter storms. For larger pruning jobs, consider hiring a professional arborist.

Wrap Vulnerable Trees

Protect young or thin-barked trees, like maples and birches, with tree wraps. These wraps shield the bark from sunscald and fluctuating temperatures. Wrap from the base up to the first set of branches and remove it in early spring.

Fertilize Strategically

Late fall is an excellent time to apply a slow-release fertilizer. This ensures the tree has access to good soil with essential nutrients to strengthen its root system over winter and bounce back healthier in spring. Avoid high-nitrogen fertilizers, as they encourage growth that won’t survive the cold.

Inspect for Pests and Diseases

Give your trees a thorough check for signs of pests, rot, or disease before winter. Look closely at the trunk, bark, and roots for any irregularities. Addressing these issues early ensures they don’t worsen during dormancy, helping your tree stay resilient and healthy when spring growth begins.

Don’t Leaf Your Trees Hanging This Winter: Trust Green Drop!

Winter in Winnipeg is as harsh as it can be, but your trees don’t have to brave it alone! With Green Drop’s expert winter tree health care, we ensure your trees stay strong and ready to bloom come spring.

From winter prep to frost-proofing, our ISA-certified arborists have got you covered in Winnipeg, Calgary, Edmonton, Red Deer, Regina, and Saskatoon.

Get your free estimate today and give your trees the care they deserve. Because healthy trees are the real gift that keeps on giving!