
Recently, the entire Chicago suburbs experienced extremely cold weather, with temperatures dropping to -9°F in some areas. Every homeowner should know that severe frost can cause significant damage to the trees around us.
A sharp drop in temperature causes physical changes to both the appearance and the internal structure of trees, leading to stress for many species and reducing their ability to regenerate.
What Signs Indicate Frost Damage on Your Trees?
Frost damage is primarily caused by extremely low temperatures and sudden temperature changes. These conditions can lead to frost damage on branches, cracks in the bark, and root damage. Even though it may be cold, the bark of the tree will be warm to the touch from the sun heating it up. As soon as the sun sets, the water within the tree flash freezes, causing splitting.
Weakened trees also become more vulnerable to biotic (living) factors, such as fungal infections and pests, which often enter through frost cracks. To protect your trees, it is crucial not only to prevent abiotic damage but also to address biotic issues promptly.
After or even during a frost event, you may notice several signs of damage:
- Bark Cracks (“Frost Cracks”)
Vertical cracks in the trunk are caused by the rapid contraction of tree tissues due to sudden temperature drops.

- Branch Frosting
If ice builds up on branches, it’s an early sign they might break eventually. Damaged branches may sag or appear unstable.

- Ice in the Soil Around the Tree
Frozen soil indicates that roots may be suffering from restricted access to water and nutrients.

What Trees Are the Most Vulnerable?
Certain tree species are more sensitive to extreme cold. These include:

- Japanese Red Maple: These ornamental trees have thin bark that is easily damaged by frost.
- Norway Maple: Often suffers from bark cracks and frostbite.
- Peach and Cherry Trees: Their buds and thin branches are especially sensitive to sudden temperature changes.
- Young Trees: Regardless of species, young trees lack sufficient protective bark and robust root systems.
To protect vulnerable trees, mulch the soil around their roots and insulate their trunks before winter. Prevention is the best defense!
How to Care for Trees During Extreme Cold
Proper care can help trees survive the cold months and stay healthy. Here are some essential tips:
- Water Deeply in the Fall
Provide trees with sufficient moisture before frost sets in. Moist soil helps roots better tolerate freezing. This is especially important for young trees that are not yet established.
- Mulch to Protect Roots
Mulch acts as a natural insulator. Create a 3-4 inch layer of mulch around the base of the tree to retain heat and moisture. Leave a small gap between the mulch and the trunk to prevent rot.
- Protect the Trunk from Frost
To prevent cracks, wrap the trunks of young trees with special protective materials.
- Pruning
Prune dead, weak, or diseased branches before winter to reduce the risk of them breaking under the weight of snow or ice. However, avoid pruning during severe frosts, as this can cause additional damage.
- Fertilizing and Soil Health
Apply fertilizers in the spring and fall to strengthen the root system.
Winter can be challenging, but with proper preparation, your trees will not only survive but
thrive in the spring. Take care of your greenery, and it will reward you with longevity and beauty.
Not sure about the health of your trees after extreme weather? Schedule a free consultation with one of our certified arborists!