Freud found that wood is usually a maternal symbol (materia=mater), and that trees are often phallic symbols.

A young male patient late in his analysis dreamed of soldiers going through a woods. In his associations he identified himself with the soldiers. That they were foreign, he associated with passive anal homosexuality and with revenge by passive resistance, or by feminine techniques, like Delilah. Going through the woods recalled his heterosexual relations, and the woods recalled early memories of sleeping in the parents' bedroom, hearing sounds, being afraid of the dark, and of curiosity about the female genital which he spontaneously felt the woods represented. But to the trees he associated the phallus, again in connection with the primal scene. In this instance then, the woods was a neat bisexual symbol, a condensation of the genitals of both sexes and, in a more hidden form, of the primal scene.