A robust model of the fully-mature, whole, healthy psyche may be described as consisting of two "dimensions," called here the "Hoop" and the "Tree." The Hoop is a horizontal dimension having to do with relationship in all its aspects. The Tree is a vertical dimension, having to do with aspiration, as well as with roots and grounding. To be fully-mature, a psyche must have both of these dimensions fully-developed and in balance with each other. The existence of the Hoop-and-Tree structure is strongly supported by evidence from the world's wisdom traditions and from modern psychology and science. The Hoop-and-Tree model shows that in essence, psychology is ecopsychology. The model also provides useful orientation in personal growth, therapy, and applied community psychology (social action).