Which trees are most susceptible to sunscald?

Young trees, newly planted trees, and species with thin bark—such as maple, ash, honeylocust, linden, and many fruit trees—are often the most vulnerable to sunscald damage.

How can I tell if my tree has sunscald?

Common signs include cracked or peeling bark, sunken areas on the trunk, delayed leaf emergence, branch dieback, and damage that typically appears on the south or southwest side of the tree.

Can a tree recover from sunscald damage?

Many trees can recover from minor sunscald injuries over time. However, severe damage may weaken the tree, increase susceptibility to insects and diseases, and require professional evaluation and management.

How can I prevent sunscald on my trees?

Preventative measures include wrapping young trees during winter, maintaining proper watering and mulching practices, protecting newly planted trees, and avoiding sudden increases in sun exposure from heavy pruning or nearby tree removal.

Sunscald: Understanding Winter Bark Damage on Trees

Q: What causes sunscald on trees?

Sunscald occurs when winter sunlight warms a tree's bark, causing cells beneath the bark to become active. When temperatures quickly drop after sunset, those cells can freeze and die, resulting in bark damage.

Many homeowners associate tree stress with summer heat, but winter conditions can be just as damaging. One common issue is sunscald, a type of bark injury caused by fluctuating winter temperatures. Understanding what causes sunscald and how to prevent it can help protect landscape trees and support their long-term health.

What Is Sunscald?

Sunscald occurs when a tree's bark experiences rapid temperature changes during the winter months. On bright winter days, sunlight can warm the bark, especially on the south or southwest side of the trunk, causing cells beneath the bark to become active. When temperatures quickly drop after sunset, these cells can freeze and die, resulting in bark injury.

The damage often appears as elongated, sunken, discolored, or cracked areas on the trunk. In severe cases, sections of bark may peel away, exposing the underlying wood.

Which Trees Are Most Susceptible?

Sunscald is most commonly observed on:

Young trees with thin bark
Newly planted trees
Trees recently exposed to increased sunlight due to pruning or the removal of nearby trees
Species with naturally thin bark, including maple, ash, honeylocust, fruit trees, and linden

Trees stressed by drought, construction damage, or other environmental factors may also be more vulnerable.

Recognizing the Symptoms

Common signs of sunscald include:

Cracked or split bark on the south or southwest side of the trunk
Sunken or dead patches of bark
Bark peeling away from the trunk
Delayed leaf emergence or branch dieback above the damaged area
Increased insect or disease activity near the injury

Because these symptoms can resemble other types of trunk damage, a professional evaluation is often the best way to determine the underlying cause.

Why Sunscald Matters

Although some trees can naturally compartmentalize and recover from minor bark injuries, severe sunscald can create long-term problems. Damaged bark weakens the tree's natural defense system and may provide entry points for insects, diseases, and decay organisms.

Repeated injury over multiple winters can reduce vigor, slow growth, and increase the likelihood of structural problems.

Preventing Sunscald

The best approach to sunscald is prevention. Several strategies can help reduce the risk.

Install Tree Wrap

Commercial tree wrap can reflect sunlight and moderate trunk temperatures during winter. Wrap young or vulnerable trees in late fall and remove the wrap in spring to prevent moisture buildup and insect issues.

Support Overall Tree Health

Healthy trees are better equipped to tolerate environmental stress. Proper watering during dry periods, mulching, and routine tree care help support vigor and resilience.

Protect Newly Planted Trees

Young trees are particularly susceptible during their first several years after planting. Monitoring and protecting these trees during winter can help prevent permanent damage.

Avoid Sudden Exposure

When possible, avoid drastic canopy thinning or the removal of nearby shade trees that may suddenly expose trunks to direct winter sunlight.

What to Do if Sunscald Occurs

If you suspect sunscald damage, avoid attempting extensive bark repairs yourself. Wound dressings and paints are generally not recommended and may interfere with the tree's natural healing processes.

Instead, have the tree evaluated by an experienced SavATree ISA Certified Arborist®, who can assess the severity of the injury, identify any secondary insects or disease concerns, and recommend appropriate management strategies to support recovery.

Professional Tree Care Can Help Prevent Future Damage

Sunscald is just one of several winter-related conditions that can affect tree health. Factors such as drought stress, root damage, improper planting, and previous injuries can all increase a tree's susceptibility to winter bark damage.

Regular inspections by an experienced SavATree ISA Certified Arborist® can help identify trees that may be at greater risk and recommend preventative measures tailored to your landscape. These may include mulching, watering recommendations, structural pruning, trunk protection, or other strategies designed to support long-term tree health.

By addressing potential concerns before they become serious problems, homeowners can help protect their investment and keep their trees healthy, resilient, and beautiful throughout the year.

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