Heavy, wet snow can bend and deform small trees and cause branch breakage or whole tree failure of larger trees. / Photo Credit: Wisconsin DNR

By Michael Hillstrom, DNR Forest Health Specialist, Fitchburg
Michael.Hillstrom@wisconsin.gov

Winter damage can significantly impact the health of trees. Keeping trees healthy through the fall is important for reducing winter stress. In dry falls, like the one Wisconsin experienced in 2024, you can help trees go into winter healthy by continuing to provide water to them until the leaves start falling (for deciduous trees) or until the ground starts freezing (for conifers).

Winter stressors include:

• Ice or wet, heavy snow breaking branches or bending young trees.
• Freeze and frost damage to aboveground parts or roots.
• Sunscald and frost cracks.
• Salt damage.
• Winter desiccation.

Trees typically recover from these issues, but repeated or severe events may kill trees or stress them enough that insects and fungi invade the following summer and cause mortality. Remove severely impacted trees to prevent the buildup of insects and diseases. Corrective pruning of damaged trees and regular maintenance pruning should be completed when trees are dormant, typically from November to March in Wisconsin.

The DNR’s Environmental Causes of Tree Damage fact sheet discusses the above winter health issues and additional environmental stressors. Minnesota Extension also has information on protecting trees during winter.