There are so many symbols in this card my head swims, but I'll discuss a few. His robe has images of the Horned God, representing wildness, humanity's essential nature, the power in self-mastery and balance. The Shaman wears the cloak of a bear, symbolizing (according to the Druid Animal Oracle, P. and S. Carr-Gomm) the unity of instinct and intuition, "primal power," and the ability to govern oneself. He has before him all the elements essential to life, and the swirling tattoos on his arms are reminiscent of the great spiral Universe.
He invites us into the dark forest to know ourselves better, and come into our power.