Bark falling off an oak in Memphis
Large patches of falling bark, especially with a crust or mat underneath, need an arborist’s assessment. The concern is both the cause of decline and whether the tree is structurally safe.
Updated November 2, 2026
What might be happening?
Tennessee Forestry describes Hypoxylon canker as a secondary disease of trees already stressed by another cause. Its signs include spore-bearing mats exposed when bark sloughs off. Oak decline can also involve drought, compaction and root damage.[12]
What to tell the arborist
Describe where the bark is coming away, whether branches are dying and any drought, digging or heavy equipment near the tree. Photograph only from outside the area a limb could reach.
The next step
Have the arborist identify the problem and assess the tree before discussing a root-zone care plan. Nearby trees may benefit from a review of avoidable stress, but care for them is not proof that the affected tree can be saved.
What not to assume
The Missouri Department of Conservation states that there is no treatment for Hypoxylon canker once symptoms develop. Confirmed disease should not be sold as something an injection or fertilizer can cure.[6]
This is general guidance, not a diagnosis. Your arborist confirms the cause and treatment suitability on site; some concerns also need laboratory confirmation.
Immediate danger from a tree or hanging limb? See 24/7 storm help. Stay away from downed lines and anything touching them; call the utility for electrical hazards and 911 for injuries.