Shedding, peeling, or splitting bark on trees in the landscape can be a concerning sight.
While not always a cause for concern, these symptoms can be harmful to the tree for many important reasons:
- The bark protects trees and their important water and food-conducting tissues located just beneath the bark from animals and mechanical injury.
- The inner bark is involved in the transport of mineral elements and the products of photosynthesis.
- Without bark, important regenerative tissues and water-conducting elements that reside just below the bark could desiccate or suffer mechanical injury.
Understanding what is causing the bark loss is an important first step to preventing further damage.
Normal Growth & Development | A Characteristic of the Tree | Extreme Weather Conditions | Lightning | Mechanical Damage | Sunscald | Frost Cracking | Smooth Patch | Insects & Diseases | Management | More Information
Normal Growth and Development
Split or cracked bark on some trees is a completely normal development. The bark of most young trees is smooth and thin. As the tree grows, the bark layer thickens, and the outermost tissue eventually dies. Continued growth pushes the bark outward, causing the outer layers to crack. On some trees, the outer dead layers peel and drop off, revealing the inner layers of bark.
Bark cracking from normal growth and development does not require any management. It is identified from other sources of bark damage by the appearance of the tissue inside the crack, which will have healthy, developing bark, with no exposed heartwood.
A Characteristic of the Tree
Shedding or peeling bark is characteristic of trees such as sycamore, redbud, silver maple, shagbark hickory, birch, and Scotch pine. For most species this characteristic develops as the tree becomes more mature. Trees with shedding or peeling bark often reveal a different colored inner bark as it falls away. Depending on the species, the inner bark may be cream, white, gray, or orange, among other colors.
In some years, trees may lose more bark than usual. Dry conditions in summer and fall and/or cold winter conditions may loosen more bark than normal, leading to the heavy loss of bark. Despite the loss of large amounts of outer bark, there is no cause for concern if the trees appear otherwise healthy. As long as there is healthy bark underneath and no exposed heartwood, no management is necessary.
Extreme Weather Conditions
Rapid fluctuations in either air temperature or soil moisture can cause bark loss. Extremes (high or low) in air temperature and/or soil moisture may also lead to peeling, shedding, or splitting bark. The reasons behind bark loss due to fluctuations or extremes are not yet well understood. Management techniques can be found below.
Lightning
Trees struck by lightning can cause long vertical strips of bark to be blown or loosened from the tree as the lightning strike follows the water-conducting vessels just under the bark down the tree, exploding the bark. A certified arborist should evaluate trees impacted by a lightning strike. Often, these trees have internal damage that may make the tree unsafe. Other management techniques can be found below.
Mechanical Damage
Mechanical damage from animals like squirrels, rabbits, and deer (antler rubbing), as well as errant lawn mowers, weed trimmers, or other equipment, can cause the bark to loosen, peel, or strip away.
This mechanical damage disrupts the water- and nutrient-conducting tissues in the tree, which are located just below the outer layer of bark.
Prevention is the key to managing this damage. Once damage occurs, there is little that can be done. If the damage occurs around the entire circumference of the trunk or branch, the tree is girdled. All growth above the girdled areas will eventually die, and for most home gardeners, replacing the girdled tree is the best course of action.
If the damage affects only a portion of the trunk or branch, the tree may recover but will more likely see decay that would impact the structural integrity of the tree and develop thinning branches, especially on the side of the tree where the damage occurred. The more extensive the damage, the longer it will take for the tree to recover. Other management techniques can be found below.
Sunscald
Cracking and peeling of bark on the south or southwest sides of young fruit trees, red maples, and lindens is frequently observed in the landscape. Often attributed to sunscald, the damaged bark comes off completely down to the wood. The loss of bark will reduce the tree's vigor and health and may shorten its lifespan. If the trunk eventually becomes completely girdled, the tree will die. Management leans on preventing future damage through proper care, in particular watering. Other management techniques can be found below.
Learn more about managing sunscald in this article: Winter Damage on Trees.
Frost Cracking
Vertical cracks in a tree's bark and wood may appear on the trunk or branches in winter. Frost cracks result from an imperfection in the wood that tends to open and close annually. Low temperatures seem to trigger the reopening, but the origins of the crack are usually traced to an injury earlier in the life of the tree. There is little management that can be done once cracks have occurred. As the weather warms, the cracks close again.
This seasonal opening and closing is stressful and may be an entry point for decay fungi and insects. Sometimes, these wounds may develop a raised area of callus tissue in an attempt to close over the wound. Management focuses on providing good care and close monitoring. Other management techniques can be found below.
Smooth Patch
Certain saprophytic fungi (those that live on dead organic matter) decompose the rough, dead outer bark of trees. This results in a condition called smooth patch (aka white patch or bark patch), which causes smooth, light, grayish patches to form adjacent to the normal, rough bark. Small patches may expand slowly over time, merging to form smooth, grayish areas several feet long. Aleurodiscus oakesii is one of the fungal species that can cause smooth patch and may occur on trees such as American elm, sugar maple, and various oaks.
Some of these fungi produce whitish fruiting structures visible on the bark, which sometimes leads to their mistaken identification as serious wood-decay fungi. These smooth patch fungi, however, do not cause cankers or internal decay. They cause no known harm to the tree, and management is not necessary.
Insect Pests and Diseases are Rarely the Primary Problem
Often, holes from feeding woodpeckers, fungal fruiting bodies, crawling insects, or other disease-causing agents are found near or under peeling or splitting bark. While these issues are not healthy for the tree, they are typically secondary invaders in areas already damaged by other causes. Understanding and addressing the primary reason for the damage will help prevent further damage from things like butt and root rot, heartwood rot, carpenter ants, and other pests and diseases.
Management of Damaged, Shedding, & Peeling Bark
Bark damage can be concerning, but the best approach is to focus on providing good care and monitoring the tree's recovery. In many cases, trees can survive bark injuries, although the long-term impact depends on the cause, severity, and extent of the damage. Trees with damage around most of the trunk's circumference may become girdled, preventing the movement of water and nutrients and often leading to tree decline or death.
Follow these steps to manage bark injuries to trees in your landscape.
Keep the Tree Healthy
Provide regular care to support recovery. Proper watering is especially important for young trees with bark damage. During dry periods, supplemental irrigation can help reduce stress and improve the tree's ability to seal over the damage.
Monitor the Damage
Check the damaged area periodically and watch for signs of decline, such as sparse leaves, branch dieback, or poor growth. Trees with limited bark loss often recover well, while extensive injuries may lead to decay and structural weaknesses over time. Trees with decay or extensive branch dieback should be evaluated by a certified arborist.
Prevent Further Damage
Take steps to prevent further damage when possible. Place mulch rings around trees to reduce interactions with mowers, trimmers, and other equipment. Make changes to the care of the tree to favor healthy growth by using proper watering and pruning techniques. Use fencing and other barriers to prevent damage from animals. Learn more in this article: How to Prevent Trees and Shrubs from Animal Damage Over Winter.
Remove Loose Bark Carefully
If sections of bark are loose or hanging, carefully remove them with a clean, sharp tool. This allows the tree to more readily seal over the damage without material in the way. Take care not to damage the surrounding healthy bark, as additional injury can slow the healing process.
Avoid Wound Paints, Dressings, and Coverings
Do not apply wound dressings, sealants, or tree paints to exposed wood. Do not permanently or temporarily cover damaged areas with tarps, burlap, plastic sheeting, metal, or any other material. Research has shown that these products do not improve healing and may actually interfere with the tree's natural recovery processes.
Do Not Attempt Bark Repairs
Taping, nailing, or tacking bark back into place is rarely successful unless done immediately after the injury (and even then, it's typically not successful). In most situations, the bark will not reattach, and efforts are better focused on supporting the tree's overall health.
Watch for Disease and Decay
Even if a tree survives, damaged areas can become entry points for decay organisms. As a result, the tree may be more susceptible to rot and structural problems in the future. Continued monitoring can help identify developing issues before they become serious. This may require evaluation by a certified arborist.
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Photo credits: 1: Aaron Steil; 2: Aaron Steil; 3: Aaron Steil; 4: Aaron Steil; 5: Aaron Steil; 6: Terry Norris; 7: Aaron Steil; 8: Aaron Steil