Bifications in the tree can appear like it has two heads. Mostly one will appear bigger or more dominant than the other. From the ground it is difficult to see the condition of the join between them. You may see
Arboricultural Reports
Be very wary of well meaning arboricultural reports and opinions on the health of trees. Defect inside of trees is difficult to spot and often the opinions expressed are not based on experience of tree removals and storm damage work.