Driven mad by his mother's insane love for him, he castrated himself under a pine-tree. The pine-tree played an important part in his cult; every year a pine-tree was decked with garlands, an effigy of Attis was hung upon it and then it was cut down.
Jung identifies the pine tree as the axial symbol in the Attis-Cybele cult, at once the locus of self-castration and the annually sacrificed cult object representing the surrender of instinctual libido to the Great Mother.
, Symbols of Transformation, 1952thesis