Why Tree Bark Doesn’t Grow Back And How To Repair It

Trunk of pine tree with peeled bark

A strong, healthy tree is a beautiful sight to behold, especially when the leaves are swaying in a gentle breeze. We know the leaves typically fall off every autumn and regrow in the spring, but does tree bark grow back? Is there anything that can be done if your trees lose large patches of bark?

While trees can repair minor instances of bark damage, major bark loss won’t grow back and instead, the tree will develop thick encrusted ridges around the missing bark. When this happens, smooth out the missing bark edges as best as possible to allow for clean regrowth.

Many reasons cause trees to lose their bark. Let’s dive in and find out what these reasons are, what can be done about it, and how—if possible—tree bark can be repaired.

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Why Tree Bark Is So Important

The tough outer layer of the tree, or tree bark, is the first line of defense. Much like our skin. The bark protects the tree from temperature extremes, keeps moisture from rain out, while keeping internal moisture in, and helps to guard against insects and animals.

Just like our skin, tree bark grows from the inside out and will shed from time to time as the new cells underneath are constantly replaced. When the growing layer of bark is damaged either by pests, environmental issues, disease, or other problems, it is unable to grow back.

The bark protects the growing layers of the tree that supply the limbs and leaves with water and nutrition. If these layers get damaged enough, it can spell certain doom for the tree. When large sections of bark get damaged or destroyed, especially if the damage goes completely around the tree, fatality increases.

According to The Department of Environmental ConservationWhen tree bark is missing or damaged it can weaken the entire tree. Think of damaged bark like a wound in your skin. It can allow bacteria and viruses to enter which can be a cause for concern.

If a tree is missing a lot of bark, or there are signs of decay, you should contact a professional to inspect your tree.

Why Tree Bark Doesn’t Grow Back

Trees can grow their leaves back, so why shouldn’t they be able to grow their bark back? Let’s look at the tree leaves like the hair on our heads. We can cut our hair down to the scalp, and it will grow back; a tree’s leaves are similar to human hair because they are constantly replaced.

The tree bark is made of different cells and so tree bark will act differently when damaged. If the outer layer of the bark is damaged, it can regrow from underneath. Trees even shed bark occasionally, especially trees like the river birch.

When the growing layer underneath the outer hard, rough, bark layer is removed or severely damaged, it can’t regenerate.

Of course, trees like the paper birch have bark that naturally falls off and grows back naturally.

What Causes Trees To Lose Their Bark? 

Trees don’t typically drop all their bark-like some people who shed their clothing as soon as they get home after a long day at work. There has to be an underlying condition or problem that makes trees lose their bark. It’s essential to their wellbeing.

Many causes such as insect infestations, animal damage, environmental factors, or human causes can damage tree bark. Let’s delve into these reasons and more to find out if there is anything that can be done to help the tree.

1. Insect Infestation

Close up termites or white ants

Many insects want to get the nutrients that trees create for themselves. Boring insects—the ones that drill holes into the trees, not the ones that drone on about uninteresting subjects—especially can cause a lot of damage to trees.

For instance, the emerald ash borer has been wreaking havoc among American ash trees; killing them by the millions. If you see peeling bark or large patches of bark that have fallen off, along with small holes in them, you might have a problem with borers. The biggest telltale sign will be D-shaped holes from where the larvae have burrowed out of the tree.

The larvae of boring insects cut tunnels through the growing layers of the tree and if the infestation is big enough, it can kill the tree by cutting off the nutrition to the leaves and rest of the tree.

Ants can also damage trees and tree bark, though they are usually attracted to trees because of other insects that produce a byproduct called honeydew. If you find ants in or around your trees, you probably have another issue with your trees such as rot or an aphid infestation.

To get rid of borers or ants in your trees, your options are pretty limited. You can either cut down and destroy the infested trees or use some kind of pesticide to get rid of the insects. We don’t recommend doing the latter yourself; it would be better to contact a professional arborist or pest control expert.

You can learn more about the trees that insects love In order to understand what trees are most at risk for insect damage.

2. Animal Damage

Many animals out there will damage the bark of trees in the food search. When food is scarce these animals will strip away the bark to reach the inner, tender areas of the tree for sustenance. Newer trees and saplings are particularly susceptible to this kind of damage.

Deer, squirrels, porcupines, voles, and rabbits can all make a meal of the tender cambium layer underneath the dry bark. This layer is the growth layer. It carries water and nutrition to the other parts of the tree and can be nutritious to animals when other sources of food are harder to find.

Bark Damage From Deer

They can strip off large sections of bark either by rubbing with their antlers or by stripping away the bark to get to the inner cambium layer. This damage looks like ragged strips and/or large chunks of bark missing from the tree a few feet off the ground.

To repair this damage, you need to trim off the ragged areas of the bark with a sharp knife. Try not to cut more healthy bark off. Then simply let the area heal on its own.

Don’t use any kind of paint or sealant as this can hinder the healing process. To help the tree heal itself better, make sure it gets plenty of water, and add some fertilizer if you haven’t done that lately.

If the tree doesn’t appear to be responding well 2 to 3 weeks, you should seek out a local arborist.

Bark Damage From Rabbits

In winter you might see evidence of rabbits chewing on your trees at the ground level. Rabbits can be especially damaging because they cannot get very high, instead, they can end up girdling the tree. Girdling happens when the bark is damaged completely around the tree and is often leads to the end of the tree.

If you see rabbit damage to your tree, the same steps as for the deer apply here. Be sure to pay special attention to the tree if it has been girdled as the tree will likely need to be removed.

Bark Damage From Squirrels

These fluffy “tree-rats” can cause damage to the tops of the trees and along branches. This usually happens in late winter when food storage becomes scarce. You shouldn’t have to worry about this damage too much because of what damage the squirrels do, the tree can usually deal with.

Bark Damage From Voles, Gophers And Mice

Except gophers, these rodents don’t usually pose too much risk to trees when they dig through the bark. Mice and voles will also nibble on the small roots of trees.

If you notice small holes and areas of freshly dug soil mounds near your trees you might have mice or voles living in the ground. Gophers dig the same types of holes, only larger. Gophers can cause serious problems to trees, especially if they are saplings.

You can use strong-smelling repellents to run these rodents off your property. Castor oil and cayenne pepper are two scents that help to run these guys off. Either pour them around their holes or mix with water and spray wherever you see the evidence.

If these methods don’t work, contact a professional pest control service to help you handle these animals. Often human methods are preferred. Most professional pest services have several ways to deal with repeat offenders.

Bark Damage From Porcupines

These walking pincushions can seriously damage trees. They can also climb very well and will often stay in a tree until it has had its fill. Porcupines will easily girdle a tree as it makes a meal of the inner layer behind the bark.

Damage by porcupines will look like shallow gnaw marks, usually around a tree and often several feet high. This kind of damage is almost always fatal for the tree. The best way to deal with porcupine damage to trees is prevention, but we will get to that just a little bit later.

3. Woodpeckers Cause The Most Bark Damage

Great spotted woodpecker (dendrocopos major)

Woodpeckers and sapsuckers can also damage the bark of a tree. While woodpeckers don’t normally damage healthy trees, the sapsuckers often do because they are looking for the sweet-tasting sap running just beneath the surface of the tree.

Woodpeckers tap at trees looking for grubs, beetles, and other insects under the bark. Unless there’s an infestation, woodpeckers will only chip away at small sections of the tree looking for food. The exception is the pileated woodpecker.

These large woodpeckers can strip away wide sections of bark looking for insects to eat. Fortunately, these birds often seek out dead or decaying trees as these attract the bugs they like to dine upon. They can occasionally attack healthy trees, but they are only looking for insects.

If you have a lot of woodpeckers on your property, you might want to have an arborist check your trees for insect infestation or you may have a lot of dead and decaying trees that need to be taken down before they cause damage.

Sapsuckers on the other hand will drill shallow holes into trees in search of the sap they feed on. They often tap holes in horizontal or vertical lines, then return a little while later to slurp up the tasty sap dripping out of the holes.

These birds don’t typically stick around for long as they are migratory and the damage they do is usually minimal. A healthy tree can quickly heal after a sapsucker comes in for a meal.

4. The Tree Has Reached The End Of Its Lifecycle

When large sections of bark fall off trees, it’s never a good sign. It could signal rot or a disease that is killing the tree. If you notice bark falling off in large sections you may be able to save it with the help of a professional if you act quickly.

Rot can set in quickly when a tree is not healthy. This often attracts insects and fungus that will help speed up the process. Depending on the type of tree it may be worth trying to keep it alive, but odds are you’ll be better off having someone cut it down for you and replace it with a new tree.

As I mentioned before, contacting a professional tree service will help you determine if saving your tree is a feasible option.

5. Sunscorch Or Sunburn

That’s right, even trees can get sunburn. This especially can happen during very hot, dry summers. Sunscorch is something that can peel the bark off a tree in the winter. Either of these events can severely damage a tree’s bark and shorten the life of the tree.

Sunscorch happens in winter, typically on the south to the southwest side of the tree trunk. When the bark is frozen because of extreme temperatures, then warmed because the sun thaws it out, sun scorch can happen.

The Utah State University Forestry Extensions explains that sunscald/sun scorch is caused by winter freezing temperatures that affect sun-warmed tissues of the tree called the cambium. The bark will start discoloring and if the injury is severe enough the bark will slough off.

Younger trees with thinner bark are more susceptible to this type of damage. The bark will peel off leaving the growing inner layers of the tree exposed to the elements. If this happens, it will shorten the life of the tree.

To prevent this on your trees, you can leave the lower branches on the trees so they help to provide shade, plant the trees somewhere they will get shade on the southern side, like near a building, or you can wrap your tree to protect from temperature extremes. This Walter E. Clark Tree Wrap is a highly recommended product to protect from sunscalds!

Sunburn on a tree is the same thing we get when we go on vacation and spend too much time in the sun. The extreme heat and constant glare of the sun on a tree’s trunk can make the bark peel just like your back after a long day at the beach. Sunburn is very similar to sun scorch except it happens in the summer months.

Drought Conditions Will Hasten Sunburn In Trees

For trees with sun scorch, keeping the trunk shaded or protected during hot, dry summer months will help to prevent sunburn. Keeping the tree watered and healthy will also help to prevent this from ruining the bark.

When planting new trees, the best time to plant them is spring and fall. Avoid planting during the summer if at all possible as the tree will not be established enough to withstand a hot, dry summer. Using a white or reflective wrap can help prevent sunburn as well.

The best way to heal your trees after either sunburn or sun scorch is to keep the tree watered and healthy as possible. Remove any dead, peeled bark so insects and fungus don’t have a place to hide and let the tree heal itself. Don’t put any sealants or covers on the injured areas as that has been proven to be detrimental.

Did You Hurt Your Tree Bark?

Close up view of old chopped off tree branch.

A tree’s bark can be damaged by trimmers and mowers as well, especially newer trees. Trees can be girdled this way. A powerful trimmer, even in professional, steady hands, can accidentally strip away bark and damage a tree in an instant.

To prevent this type of damage you can plant ground cover around the trunk of the tree or add a bed of mulch. Just leave an indention a few inches to a foot out from the base of the tree. You want your mulch to resemble a donut around the tree.

If you accidentally damaged your tree’s bark, take a look at our guide on how to save a tree with stripped bark here!

Fungi And Tree Bark

Bad jokes aside, hypoxylon canker is a fungus that can cause tree bark to fall away in large sections. If you see a fungus growing underneath the peeling bark, along with dying branches and yellowing leaves it’s probably hypoxylon canker.

If you are having trouble with disease and fungi targeting your trees, consider using something such as this BioAdvanced Concentrate product!

Unfortunately, there isn’t much that can be done if this fungus sets in your trees. The best thing to do is to remove the tree and destroy the wood to prevent it from spreading to nearby trees and shrubs.

Preventing Tree Bark Loss

A strong, healthy tree is the best prevention from factors that can damage or drop bark. Proper watering, fertilizing, and trimming of your trees will be able to handle most problems. When trees are healthy, they are much more capable of healing wounds, fighting off insects, and preventing issues.

Munching critters on the other hand might be a bit tougher to prevent. If you have problems with rodents like gophers, rabbits, and ravenous porcupines, the best way to keep these pests off your trees is to wrap the trunks with a wire mesh. Something like these Andwarmth Tree Protectors will help protect against most animals.

If you have issues with porcupines, you might have to go a little more extreme as these prickly characters are great climbers. You might have to employ some catch and release traps or attach some electric fence wire around your trees to keep porcupines away.

How To Save A Tree With Damaged Bark

As we’ve mentioned before, tree bark can’t grow back. The tree can heal itself if the damage isn’t too extensive though.

What you can do to help the tree after the bark has been damaged is to remove the jagged edges of the bark but be careful not to expose any more living tissue underneath. Use a sharp knife or chisel to round off the edges. Then just keep the tree healthy and let it heal on its own.

For one of the most common type of yard trees in the United States, check out our guide on the reasons why bark is falling off your oak tree and how it fix it!

Don’t Use Sealants

Just because they are out there doesn’t mean you should use them. Arborists and plenty of scientific studies say that sealants don’t help trees to heal. They can do the opposite and depend on what kind, they can offer hiding places for insects and fungus.

Girdled Trees

If the bark damage goes completely around the tree, all you can do is keep an eye on it and see if the tree can bounce back. A girdled tree has very little chance of healing itself as the layer of tissue that provides the rest of the tree nutrients and water is damaged.

If the tree seems stunted, leaves start dropping before autumn, or it doesn’t grow at all, you will have to remove the tree. There’s nothing else to be done.

That’s A Wrap!

Trees can regrow leaves and new branches every year, but when a tree loses its bark, it is incapable of growing back. There are a lot of things that can damage a tree’s bark such as animals, fungus, or environmental factors, and healthy trees typically can heal themselves if the bark damage isn’t too severe.

When tree bark is damaged, with a little knowledge and professional help, you can decide if the tree needs to be removed or if it will heal and continue to provide shade and beauty. 

References:

Baxter, R., and L. Hansson. “Bark consumption by small rodents in the northern and southern hemispheres.” Mammal Review 31.1 (2001): 47-59. https://doi.org/10.1046/j.1365-2907.2001.00078.x  

Villari, Caterina, et al. “Progress and gaps in understanding mechanisms of ash tree resistance to emerald ash borer, a model for wood‐boring insects that kill angiosperms.” New Phytologist 209.1 (2016): 63-79.  https://doi.org/10.1111/nph.13604 

Verheyden, Helene, et al. “Variations in bark‐stripping by red deer Cervus elaphus across Europe.” Mammal Review 36.3 (2006): 217-234.  https://doi.org/10.1111/j.1365-2907.2006.00085.x 

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