Surviving the Storm Preparing Trees to Stand Up to Winter By TJ Yurko, ISA Certified Arborist (PR-5403A), ISA TRAQ, CLHT
As winter tightens its icy grip across North America, preparing trees for the cold months ahead is par- amount. Heavy snow, frigid ice, and fierce winds can transform enchanting winter wonderlands into bone-chilling graveyards for trees, leaving them vul- nerable to damage that poses serious safety hazards and a significant risk of injury. Luckily, there is a way to weather the storm. By con- ducting comprehensive risk assessments and ad- dressing other critical preparatory tasks, trees can be fortified against the winter elements to safeguard not only people and property but also promote their health and resilience to ensure they remain steadfast and beautiful all year round. RISKY BUSINESS Winter storms pose a significant threat to trees, with elements like snow, ice, and wind, often leading to substantial, irreversible damage. Trees that are poorly maintained, structurally deficient, shallowly- rooted, weak, or stressed are especially vulnerable to harsh winter conditions as they lack structural in- tegrity and mechanical strength compared to healthy, deeply-rooted trees. While healthy trees stand a
better chance of surviving stormy weather, this does not mean they are immune to risk. In tree biomechanics, failure occurs when load exceeds strength, either through overload failure (i.e., single load application) or fatigue failure (i.e., repetitive load over time). In other words, when forces like snow, ice, and wind are above the tree’s capacity to support that load, whether suddenly or gradually, it fails. This principle is true for any tree — not just weak or stressed trees. This is why even healthy, structurally sound trees can suddenly succumb to extreme weather forces. Winter conditions can generate both overload and fatigue failure in a tree’s architecture, which dramatical- ly increases the likelihood of failure during storms. Contributors to failure are not limited to snow, ice, and wind. Freeze-thaw cycles caused by day-night temperature fluctuations can result in vertical cracks or sloughed bark, exacerbating weak structure and exposing the tree’s vascular system to disease and decay. Additionally, pollutants such as de-icers can cause chemical imbalances in the soil, leading to physiological problems like desiccation and nutri- tional deficiencies.
ArborTIMES™ Winter 2025 | 9
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