Gardener hotlines receive many calls this time of year from gardeners concerned about bark that’s peeling or flaking off of their trees. While that can be bad news, peeling tree bark often isn’t a problem at all.

Some tree species naturally shed their bark, such as:

• Birch
• Paperbark maple
• Kousa dogwood
• Crape myrtle
• Stewartia
• Parrotia
• Sycamore

People just tend to notice bark-peeling more in fall when trees drop their leaves, shining the focus on what’s left, i.e. bare branches and tree trunks.

The first thing to do before panicking is to make sure you aren't looking at a tree whose bark is naturally peeling, flaking, or sloughing off.

Bark loss: normal or not? 

Two other clues help determine whether it’s time to worry or not.

One is whether you see younger bark underneath the older peeling or flaking bark. Normal bark loss is typically thin and is being “pushed” off as the new bark grows. If thick chunks of bark are coming off and you can see only smooth, bare, trunk wood underneath, that’s a bad sign.

The second clue is how the tree is doing overall. If the tree grew normally during the past season, had normal-sized leaves, produced a good leaf canopy with good color, isn’t sporting branch diebacks, and looks otherwise healthy, it’s most likely a normal or non-threatening bark loss.

When is bark loss bad for trees?

Now for the bad news.

Sometimes bark loss means a tree is in trouble – or is already dead.

Dead trees ultimately lose their bark – sometimes while still standing, sometimes not. But they’ll also give you other clues, such as dropping foliage, branches that become brittle, and branch wood that shows no green when you scrape into it.

A dead tree will eventually fall, so if that’s what you suspect, call a tree company ASAP to 1.) confirm the tree is dead, and 2.) remove it if it is.

Short of that, bark loss can be a sign that something is threatening tree health, ranging from relatively localized or minor, healable assaults to the beginnings of a potential slide toward dieback or death.

Survivable evils include frost cracks, small lightning strikes, wounds from bad pruning or storm tear-offs, and wounds from rodent chewing or deer antler rubbing. So long as the tree doesn’t become infected and hasn’t lost its critical cambium layer the whole way around inside the bark (a malady called “girdling”), recovery is possible.

Tree Disease, Rot, and Infection

The prognosis is more foreboding if you’re seeing sunken soft spots in the trunk, leaking sap, or mushroom-like growths in addition to bark loss. Those are signs of disease, rot, or infection that can spread beyond the tree’s ability to compartmentalize the damage. That’s a threat to the entire tree.

Wood and root-rot diseases are difficult to stop once they get going. If you have a valuable tree and suspect disease, a tree company might be your only hope. 

Leaf Diseases & Insects

While leaf diseases and leaf-attacking bugs like Japanese beetles and caterpillars are generally cosmetic and non-life-threatening issues, boring insects are a different matter. They do their damage when the larval stage feeds on the inner wood, safely out of the reach of predators and most insecticides.

Good spray timing and/or using systemic insecticides (ones taken up by the roots or injected into trunks) are the way to stop borers before they kill a tree.

Weather & User Error

Then there are troubles related to weather (either drought or soggy conditions) and to “operator error,” including planting too deeply, over-mulching, and “mower blight” (when homeowners repeatedly damage trunks by bumping into them with lawn mowers or horse-whipping them with string trimmers).

In any event, pay attention to that bark now that it’s more noticeable. It might be just shedding its bark naturally or it might be experiencing a more serious problem.