If you’ve noticed cracked or peeling bark on one side of your tree, especially during late winter or the peak of summer, you may be dealing with a common yet often overlooked issue: sunscald.
As the leading expert tree service in Lexington, Kentucky, we share this guide to understand how to treat sunscald on trees to protect your landscaping investment. Tree Care Inc. sees this problem regularly, especially with young or thin-barked trees like red maples, dogwoods, and crabapples.
What Is Sunscald?
Sunscald, sometimes referred to as “southwest injury,” is a type of tree bark damage that typically affects the south-facing exposure of a tree’s trunk. It occurs when warm daytime sun, particularly in winter, activates dormant cells in the bark.
The activated cells are then killed when nighttime temperatures drop suddenly. That leads to cracking, peeling, or sunken bark.
Sunscald can also happen in summer when intense sunlight overheats bark that lacks shade, especially on newly planted or recently pruned trees.
In both types of seasonal sunscald, the result is dead bark tissue that compromises the tree’s health and opens the door to pests and disease.
Why Lexington Trees Are at Risk
Lexington’s climate makes many of our local trees especially vulnerable. With cold but often sunny winters and hot, humid summers, temperature fluctuations can be extreme. As you know, we have some swings of more than 50°F in less than a day. That’s particularly dangerous for:
- Thin-barked species like sugar maples, red oaks, and dogwoods
- Newly planted or juvenile trees
- Trees in wide-open yards with full sun exposure
Signs Your Tree Has Sunscald
The beginning stages of sunscald can be very subtle, and it’s easy to miss damage until it’s well underway. Knowing how to treat sunscald on trees means looking for these symptoms, typically on the south-facing exposure of your trees:
- Discolored, sunken bark (often reddish-brown or yellow)
- Vertical cracks in the bark
- Peeling bark exposing smooth, light-colored inner wood
- In severe cases, fungal growth, oozing sap, or insect infestation
Without proper treatment, sunscald wounds can lead to decay, structural instability, or even the death of the tree.
How To Treat Sunscald on Tree Bark
Trees are remarkably resilient, but sunscald wounds still require careful attention. Here’s what arborists generally recommend or perform directly to deal with sunscald.
1. Gently Remove Dead Bark
Use a clean, sharp knife sterilized in a 10% bleach solution to carefully remove loose or peeling bark around the wound. Never rip off bark or cut into healthy tissue. The goal is to remove debris while minimizing further damage.
2. Skip Wound Dressings
Although it’s tempting to seal the wound with paint or tar, avoid commercial wound healing compounds. Scientific research shows these products can trap moisture and pathogens. In most cases, an arborist will elect to let the wound air dry naturally so the tree can compartmentalize the damage on its own.
3. Boost Tree Health
Knowing how to treat sunscald on trees involves ordinary best practices during recovery:
- Water deeply during dry spells, especially in summer. Aim for one to two inches of water per week.
- Apply two to three inches of organic mulch around the tree’s base without touching the trunk to moderate temperatures and hold moisture.
- Fertilize in early spring with a balanced, slow-release formula, based on an expert soil test.
4. Use Protective Tree Wraps
In late fall, wrap the trunk in protective tree wraps made from breathable materials like kraft paper or Treekote. These materials protect against dramatic temperature fluctuations and reflect sunlight.
Leave the wrap on during the winter and remove it in early spring to prevent moisture buildup and insect nesting. In summer, loose wraps or temporary shade cloth can help prevent sunburn on tender bark.
Prevention Is the Best Cure
Here’s how to help prevent sunscald before it starts.
Smart Planting Practices
Avoid placing trees in full south-facing exposure without natural shade from larger trees, fences, or buildings as they mature. For sensitive species, choose planting spots that receive partial shade, especially during sunny winter afternoons.
Choose the Right Trees
When possible, opt for native or well-adapted species with thicker bark. Red oaks and white oaks, for instance, handle Lexington’s climate better than paper birch or Japanese maple while young.
Apply White Paint for Extra Protection
For fruit trees or newly planted ornamentals, a 50/50 mixture of white latex paint and water applied to the trunk can reflect sunlight and reduce heating. Consult your arborist about how to treat sunscald on trees with this helpful practice in orchard-style settings or open yards.
Use the Correct Pruning Techniques
Over-pruning is one of the fastest ways to expose bark to harmful sun. Work with your tree service company to employ careful pruning techniques to shape your tree while leaving lower branches intact for shade.
When To Call Tree Care Inc.
While minor bark damage from sunscald may heal on its own, some situations call for expert care.
Contact Tree Care Inc. if the wound spans over 25% of the circumference of the trunk, there’s visible decay or fungal growth, sap is oozing, or the tree appears unstable. You should also reach out if you’re unsure how to treat the damage or apply protective wraps.
A certified arborist can assess your tree’s condition, recommend treatment, and provide structural support if needed. Experts use advanced solutions like precision pruning, grafting, and cabling when appropriate to promote recovery and prevent further decline.
With local knowledge and professional tools, Tree Care Inc. helps Lexington homeowners protect their landscape investments. Don’t wait until the damage worsens if you notice the classic symptoms of sunscald we’ve described.
Count on Tree Care Inc. for Expert Tree Services in Lexington
If your trees are showing signs of stress, or if you want to prevent problems before they start, Tree Care Inc. is here to help. Now that we’ve discussed how to treat sunscald on trees, you can count on us for comprehensive expert tree care services, including pruning, maintenance, disease diagnosis, and preservation.
Call us today at (859) 347-2237 to schedule a consultation with one of our certified arborists.
