Tree limbs are connected to trunks by interlocking layers of wood, forming an enlarged "branch collar". Instead of just abutting the surface, trunk tissues grow around and envelop the branch base each year, creating a structurally reinforced and flexible joint. However, in some cases, this union is not as ideal, and what are known as Bark inclusions.

Bark inclusions in trees occur when two upright branches or stems grow too tightly together, trapping bark between them instead of fusing with solid wood. This creates a weak, V-shaped crotch that makes the tree highly susceptible to splitting under heavy fruit loads, ice, wind, or other factors.