For many homeowners, it’s easy to assume that the garden is safely dormant until spring (which very often means you can retreat inside where it’s toasty warm). However, for the trees on your property, the winter months can be the most physically demanding time of the year. While trees have evolved to withstand cold temperatures, the combination of harsh winds, fluctuating freeze-thaw cycles, heavy snow loads, and hungry wildlife are some common reasons why trees can end up injured in winter. These injuries often go unnoticed until the snow melts, leaving the homeowner with damaged bark, broken limbs, or trees that fail to leaf out.
Protecting your trees properly requires proactive measures. By understanding the specific threats posed by the cold season, you can implement barriers and maintenance routines that ensure your trees emerge from winter with their health and vigour intact. Here are the essential steps for protecting tree bark and branches this winter.
1. Guard Against Sunscald
One of the most common winter afflictions for young trees, particularly those with thin bark like maples and fruit trees, is sunscald. This issue typically occurs on bright, sunny winter days when the direct sun heats up the bark on the south or southwest side of the tree. The warmth causes the dormant cells beneath the bark to wake up and become active.
Consequently, when the sun sets or is obscured by clouds, the temperature can drop rapidly, sometimes by tens of degrees Celsius in a matter of minutes. This sudden freeze kills those newly active cells, resulting in unsightly, sunken patches of dead bark that may eventually crack and peel.
To prevent this, it’s essential to wrap the trunks of vulnerable, young trees; young trees require some help to ensure they make it through winter safely. Use a commercial tree wrap made of light-coloured material, such as crepe paper or burlap, which reflects sunlight and keeps the bark temperature stable. Start wrapping from the base of the soil and spiral up to the first major branches, overlapping each layer by about one-third.
2. Prevent Frost Cracking
Similar to sunscald, frost cracking is caused by extreme temperature fluctuations. However, this damage manifests as deep, vertical splits in the trunk. These cracks occur when the inner wood and outer bark expand and contract at different rates during rapid cooling. One indicator that frost cracking’s happened in your trees is a loud, gunshot-esque sound when it happens.
While frost cracks often close in the summer, they reopen in subsequent winters and can provide an entry point for disease and insects. Ensuring your trees are well-watered in the autumn is a primary defence. Additionally, maintaining a layer of organic mulch around the base—about 5 to 10 centimetres deep—helps insulate the root zone and regulate moisture, reducing the stress that leads to cracking.
3. Install Physical Barriers for Rodents and Deer
When the ground is covered in snow, food becomes scarce for wildlife. Mice, voles, and rabbits often turn to the nutrient-rich inner bark of trees for sustenance. If these animals chew the bark all the way around the trunk (girdling), it cuts off the flow of nutrients and can kill the tree.
To stop rodents, install hardware cloth or a cylinder of wire mesh around the trunk. The mesh should be buried 5 to 8 centimetres into the soil to prevent burrowing and should extend at least 50 centimetres above the anticipated snow line. For larger threats like deer, which browse on buds and twigs, you may need taller fencing or burlap wraps around lower branches.
4. Manage Heavy Snow and Ice Loads
Heavy accumulation of wet snow or ice can bend branches to their breaking point. This is particularly dangerous for multi-stemmed evergreens like junipers or arborvitae. When branches break, they leave jagged wounds that are difficult for the tree to heal.
If you notice snow piling up, gently brush it off with a broom using an upward, sweeping motion. Always take care not to strike the branches to shake the snow off; in freezing temperatures, wood becomes brittle and can snap easily upon impact. If branches are coated in ice, it is best to leave them alone. Attempting to chip away the ice usually causes more damage to the bark and buds than the ice itself.
5. Hydrate to Prevent Winter Burn (Desiccation)
Winter winds are incredibly drying. Evergreens are susceptible to “winter burn,” where the needles lose moisture to the wind faster than the frozen roots can replace it. This results in brown, scorched-looking needles on the windward side.
The best prevention begins before the ground freezes. thoroughly water your trees throughout late autumn until the first hard frost. This ensures the tree’s cells are fully hydrated. For particularly exposed evergreens, consider erecting a barrier using burlap and stakes on the south and west sides to block the prevailing winds and harsh sun.
6. Mitigate Salt Damage
If your trees are located near a road, driveway, or sidewalk, they are at risk from de-icing salts. Salt spray from passing vehicles can coat buds and twigs, causing them to dry out and die. Furthermore, salt runoff can accumulate in the soil, preventing roots from absorbing water and nutrients efficiently.
To protect bark and branches from spray, a physical barrier of burlap is most effective. Regarding soil health, try to use alternatives to sodium chloride, such as calcium magnesium acetate, or use sand for traction instead. If salt use is unavoidable, flush the soil around the tree with fresh water heavily in the early spring to dilute the salinity. While you’re at it, educating yourself on tree salt damage and what you can do about it gives you more options for looking after the health of your trees in the future.
A Final Note on Pruning
While you are inspecting your trees for protection, you might be tempted to prune. It is generally best to wait until late winter (February or March) when the tree is fully dormant but the worst of the freeze is over. Pruning in early winter can leave fresh wounds exposed to extreme cold, leading to dieback.
Winter acts as a rigorous test for your landscape, but a little proactive care makes all the difference for your trees. Wintertime is an excellent time to care for your trees or plant a privacy tree at home in preparation for the coming year. With these measures in your arsenal, you can take some effective steps to safeguard your investment against the elements. A little effort now ensures your trees emerge healthy, resilient, and ready to flourish when the spring thaw arrives.
When you need a hand finding the right shade and privacy trees for your home, Caledon Treeland is here to help. We provide a wide range of shade trees to match your home’s size and climate, ensuring your trees offer what you need and stay healthy to keep doing so. Give us a call now at (905) 880-1828 to visit our tree farm and find the right tree for your home.