Eva – If you apply the ground rules to your dream – that every character, animal and thing in your dreams are usually yourself in some way, then it begins to make sense. Considering that you as a person have many, many parts to you, starting with your body, your awareness, you memories, the many shades of emotion, the instinctive drives, the mental factors, the unconscious functions, the spirit, and if you put them together in a drama, and each had a different image attached to it, you can get a feel for your dream.
So you are surrounded by natural growth supported by manmade structures. Even so it is limiting because you can see a door - a boundary; a barrier to change or growth; the passing from inside oneself to exterior life or vice versa.
Then the snake, an embodiment of your instinctive self, the poisonous or creative emotions that can drive or rule us. You have to kill it before you can get to something better/bigger. But as it gets nearer it transforms into a woman’s face. Pity you didn’t let it get right up to you – ground rule 12 In the world of dreams our most intimate fears and longings are given an exterior life of their own. 13 You cannot be killed in a dream. All you can experience is the anguish and perhaps fear of dying, but in dreams you cannot die. 14 In dreams, what ever moves away from you in our dreams is going out of your life; and whatever moves toward you is emerging into consciousness. – it would have then become fully known as yourself; the poisonous emotions you were fighting.
So it seems you have had a long struggle with yourself and have gained the strength maybe through the control of yoga to kill the beast that you are. We will have to wait and see whether this will free you and allow a wider sense of yourself. See
http://dreamhawk.com/dream-encyclopedia/dream-yoga/Blessing on your journey.
Tony