Included bark forms when bark becomes embedded inside a branch or stem union as the tree grows, reducing the amount of normal wood connection through the union.
Why does it matter?
Included bark can reduce attachment strength. It is especially important when it occurs between large co-dominant stems because failure can release a substantial portion of the crown.
What does it look like?
It is often associated with a tight seam or V-shaped union. Appearance alone does not quantify risk; tree size, loading, decay, cracks, exposure and targets all matter.
What should you do?
Avoid attempting to split, drill or heavily prune a large union yourself. An arborist can assess whether monitoring, pruning, support or removal is appropriate.