Codominant stems, trunk and branch structure
Trunks need enough wood tissue arranged appropriately to hold the tree up in stormy weather. Branches well attached to the trunk can remain secured for a long time (left and center photos). Weakly attached branches (right photo) can split from the tree. Trees with weakly attached branches fail more often than trees without these defects.
The two codominant stems on the right are weakly attached because they are the same size and because of the bark inclusion between them. The codominant stems below are better attached because there is no bark inclusion. Cabling and bracing can be used to help hold certain trees together (See: cabling and bracing). Trees can also be structutally pruned to either prevent or modify the impact of this defect.