What is inclusion bark?
Trees are supposed to form wood-to-wood connections at branch unions
With inclusion bark, the tree forms bark-to-bark contact instead
Bark cannot support weight or movement
Over time, the two stems push against each other rather than strengthening together
Think of it like trying to glue two boards together with cardboard between them—it will always be weak.
Why inclusion bark is bad 🌳⚠️
1. Structurally weak
No strong wood connection
The union relies on pressure, not strength
Prone to splitting under load
2. High failure risk
Common point of failure during:
Wind Ice and snow Storms
Heavy foliage or canopy weight
Failures often happen suddenly with little warning
3. Creates internal cracks
As stems grow, pressure forces them apart
Cracks form deep inside the tree
These cracks allow:
Water intrusion
Fungal decay
Insect entry
4. Gets worse with age
The longer it grows, the tighter and weaker it becomes
Large co-dominant stems with inclusion bark are especially dangerous
5. Common in urban & fast-growing trees
Frequently seen in:
Maples
Bradford pears
Elms
Ash
Redbud
Especially trees that were not pruned young
How to spot inclusion bark
Tight V-shaped crotch (not a wide U)
A visible seam or crack running down between stems
No visible branch collar
Bark looks “pinched” inward
Can it be fixed?
Young trees:
✔ Corrective pruning can reduce risk
Mature trees: ⚠ Often cannot be fully corrected
May require:
Structural pruning
Cabling/bracing
Or removal.
