The oak tree occupies a structurally privileged position in the depth-psychological corpus, functioning simultaneously as archetype, cosmological symbol, and vessel of individuation. Jung establishes the oak as the paramount figure among the living contents of the unconscious — ‘the king of the forest’ — and identifies it explicitly as a prototype of the Self, the symbol of the source and goal of the individuation process. This reading resonates through the Jungian tradition: in alchemy, the oak designates the philosophical tree, the hollow vessel, and the hiding place of Mercurius, thereby encoding the entire opus in a single image. Hillman extends the symbolic register outward, proposing the oak as a ‘soul tree’ par excellence — inhabited by nymphs and diviners, capable of speech, carrying in its acorns the compressed foreknowledge of centuries. The Zhuangzi tradition, present through Watson’s translation, contributes a paradoxical counter-theme: the serrate oak as the supremely useless tree, which by virtue of its uselessness attains sovereign longevity — a tension between instrumentality and sacred autonomy that Jung himself cites approvingly. Neumann situates the oak within the feminine chthonic stratum, invoking Bachofen’s reading of the ‘nocturnal oak’ as the dark womb of the Great Mother. Together these voices reveal the oak as one of the most overdetermined symbols in the corpus: king and vessel, soul-voice and death-mother, self and prima materia.