Why is bark falling off my tree?
Bark lifting in strips, plates, or sheets — sometimes revealing smooth pale wood, sometimes sawdust and insect tunnels underneath.
Not an emergency this afternoon, but the window for a useful response is measured in weeks. Left alone, most of these get more expensive rather than less.
Some species shed bark as a matter of routine and should be left alone. Everywhere else, bark comes off because the living tissue underneath died, and the question becomes how much of the trunk's circumference is involved. Under a quarter is usually survivable. More than half around the trunk means the tree's supply line is cut, and the decline that follows is not reversible.
What this looks like
Start with whether the bark that is falling was ever alive. Sycamore sheds jigsaw plates and shows cream and olive underneath; lacebark elm flakes into an orange-and-gray mosaic; river birch peels in curls. That is normal and healthy. Bark separating over dead wood looks different: it lifts at the edges, is often on one side of the trunk, and what shows underneath is dry, stained, tunneled, or gray rather than fresh and smooth.
- An area of loose bark with a defined edge, usually on one aspect of the trunk
- A raised callus ridge where the tree is trying to grow over the dead area
- Sawdust-like frass, winding tunnels, or beetle galleries visible when a flap lifts
- Long vertical strips torn away, running from high on the trunk toward the ground
What causes it in Kansas
Roughly in order of how often each turns out to be the answer here. The line under each one is what separates it from the others — open a cause for the detail.
1Normal exfoliation
How to tell: It happens uniformly over the whole trunk, the tree is otherwise healthy, and the newly exposed surface looks fresh and smooth.Sycamore, lacebark and Chinese elm, river birch, shagbark hickory, and mature honeylocust all shed bark as part of ordinary growth. The wood beneath is sound and evenly colored.
2Southwest injury and sunscald
How to tell: A vertical dead strip on the south or southwest side of a young trunk, sometimes with a crack down its middle.On a clear Kansas winter afternoon, the southwest face of a thin-barked trunk warms substantially above air temperature, then drops below freezing at sunset. The cycle kills cambium in a vertical strip. Young maple, linden, honeylocust, and recently planted trees are the usual victims, and trees that just lost the shade of a neighbor are at particular risk.
3Cankers
How to tell: A sunken, discolored, sharply bordered area with a callus ridge around it, often with dieback in the branch above.Fungi that colonize the living layer through a wound and kill an expanding patch of it. Cytospora on spruce and poplar, Nectria on maple and honeylocust, and Botryosphaeria on drought-stressed trees are the common Kansas cankers.
4Borer galleries
How to tell: Tunnels packed with fine sawdust under the loose bark, plus exit holes in the bark surface.Larvae feeding beneath the bark kill the tissue that holds it on. Bark loosens over the tunneled area and eventually falls, and woodpeckers hunting the larvae speed the process.
5Mechanical and animal damage
How to tell: Damage confined to the bottom eighteen inches, or a shredded strip at deer-antler height with the wood scarred underneath.String trimmers and mower decks kill bark at the base a little at a time. Bucks rub velvet off antlers on small trunks in autumn. Rabbits and voles gnaw bark at the snow line in winter.
6Lightning
How to tell: A single long, narrow scar running most of the height of the trunk, appearing after a storm.A strike boils the moisture under the bark and blows a strip off, often spiraling from the top of the tree toward the ground.
What to do, and what to avoid
Safe to check yourself
All from the ground — no ladder, no saw.
- Confirm the species first, because for several Kansas trees this is a non-event
- Press a thumbnail into the exposed wood: firm and moist is live, dry and crumbly is not
- Estimate what fraction of the trunk's circumference is affected at the worst point
- Look directly above the damage — a thinning or dead section of crown above a wound tells you the injury reaches the tissue that matters
What not to do
The responses that make this one worse or permanent.
- Do not pull loose bark off to tidy it up; you tear away tissue at the margin that is still alive and trying to close the wound
- Do not apply tar, pruning paint, or wound dressing, which seals moisture in and slows compartmentalization
- Do not wrap the trunk permanently — wraps left on for years trap moisture and insects
- Do not mow or trim closer than a mulched ring around the base, since the base is where most bark injury starts
When to contact an arborist
Whatever this narrows it down to, the assessment that decides what happens next has to happen at the tree. Why that is
Common questions
My sycamore drops bark every summer. Is that a disease?
My sycamore drops bark every summer. Is that a disease?
No. Sycamore sheds plates of bark as the trunk expands, exposing the pale cream and olive surface that gives the species its look. It is one of the most reliable ways to identify the tree from a distance.
Should I paint or seal the wound?
Should I paint or seal the wound?
No. Decades of research point the same direction: wound dressings do not prevent decay and can hold moisture against the injury. A clean wound left open, with the tree kept watered, is the best available outcome.
How do I prevent winter sunscald on a young tree?
How do I prevent winter sunscald on a young tree?
Use a light-colored trunk wrap or a white tree guard from November through March for the first few winters, and remove it each spring. Keeping the tree adequately watered into late fall helps as well, since dehydrated bark is more vulnerable.
Kansas Tree Guide is an independent educational resource. Nothing on this site replaces an on-site assessment by a qualified arborist or tree-care professional. Last reviewed August 2026.
Often seen alongside this
A second symptom narrows the cause faster than more detail about the first.
Not what you are seeing? Work the symptom guide again.