Tree diagrams are methods for illustrating hierarchy. The diagram is a tree-like structure, with connecting lines extending from a central node. The central node is often referred to as the "root node," the connecting lines as "branches," the connected members as "nodes," and finally the "leaf nodes" being the members with no further extensions. Simple shapes such as rectangles or circles are commonly used as nodes, with descriptive text within or underneath the shape.
Tree diagrams are effective means to display organizational hierarchy, such as a chain of command, and they provide clear information regarding reporting lines and departmental structure. They can also be used to visualize family relations and descent, which is known as a "family tree."