Leonard Mink, owner of Leonard Mink Tree Service says that Co-Dominant stems or trunks are where 2 or more branches are coming from the same place and are close to or equal diameter. This makes the tree structurally weaker than a single trunk. The lower the crotch or split is, the more weight or stress is on each stem. Which means the lower the crotch/split the less sound the tree is. Cracks can form due to this stress, and make the tree more likely for structural failure or “splitting off”. Water can also be trapped in the crotch/split which aids in speeding up decay. If you have a tree with a co-dominant stem, call Leonard Mink Tree Service to have it inspected.