Wisdom is a tree of life … (Sayings of Salomo, Proverbs 3:18)
Standing next to an ancient tree awakens feelings of reverence and security within us. The tree reveals something of its beauty, stillness and sacredness. It reflects the vastness of our innermost being.
Trees and humans are kindred spirits. The tree, standing tall between heaven and earth, mirrors the human being, a reflection of the new human being.
We become aware how trees and humans are related. Reflecting deeply on the essence of trees, we recognize the similarities and thus, receive inner wisdom of the laws of life, as well as the dynamics of consciousness between heaven and earth.
Standing tall between heaven and earth
Standing up straight and the subsequent upright stride was an enormous evolutionary step for humanity. From the millions of species on earth, only humans and their immediate predecessors managed this feat. As babies, we once again retrace this evolutionary step. We start as quadrupeds and gradually learn to stand up. In the plant kingdom, only trees (along with their "predecessors", grasses and stalks) stand up, literally sticking out of the vegetation.
"The tree is the human being among the plants", as stated by the sound researcher and musician Joachim-Ernst Berendt. 
There is a path, a”road” between heaven and earth. A flux of energy flows up and down. The roots bring nourishment and strength on the upwards journey, the leaves absorb carbon dioxide and solar energy from the air, produce water and sugar (glucose) through photosynthesis and a viscous glucose sap is sent to the roots. In turn, oxygen is released through the leaves into the air.
In humans, too, an energetic "road" exists to the left and right of the spine, through two nerve cords. This brings about a creative-revealing, ever-renewing flow of energy and creates a high vibrating energy field and consciousness around us.
Yggdrasil - The World Tree
Germanic mythology tells us about Yggdrasil, the World Ash Tree. The tree stands in the center of the world and, as the axis of the world, connects the three levels of heaven, the middle world and the underworld. Similarly, a world axis also passes through us. We are the connecting link between heaven and earth. Spiritually, a constantly renewing flow of energy circulates between the poles of the earth logos (the divine earth core) and the sun logos.
Yggdrasil, the World Ash Tree, is an image of creation as a whole. It is also the symbol of life - decay and growth, the cycle of constant renewal. The animals partake of its life force; the three Norns (women of destiny) spray it with the holy water from the Urd well, thus continuously replenishing its life force. Yggdrasil is evergreen because its life is continually and mysteriously renewed. The World Ash Tree is a symbol of immortality.
For us humans, it is a mirror. We are called upon to become cosmic human beings through a process of transformation. We develop a consciousness that reaches beyond the spatial-temporal. The myth of Yggdrasil gives us clues how this can happen:
For nine days Odin hangs himself from this world tree. Together with his lance, he ties himself with ropes and surrenders. Odin sacrifices himself, as he suspects he will receive the secret knowledge lying at the roots of the world ash.
For Odin, the world ash tree is a sacrificial tree and a tree of knowledge. For nine days and nights Odin hangs upside down on the sacrificial tree without food or liquids, wounded by his own spear. After nine days he falls down to the roots of the tree – and there he can gain access to the secret wisdom. In Germanic mythology, the number nine is significant, because it represents the nine levels of existence, the nine dimensions of consciousness.
What is the significance of the roots? In the Yggdrasil myth, the three women, destiny Urd (fate), Verdandi (the becoming), and Skuld (that which is to be) dwell at the base of the tree. This trinity of the feminine keeps the secret of life to itself and only passes it on to the one who has proven to be suitable and steadfast through his total self-sacrifice.
What does this ancient Germanic tree myth have to do with our lives?
Injury and consciousness
Every tree has a vulnerable spot. We now know that the flowing, water-conducting layer must not be destroyed, otherwise the tree would die. Its energy flow would be interrupted. Similarly, it is also essential for us humans to keep the inner flow of energy moving , to free it from injuries, blockages, false beliefs.
"Every time you feel bad, honestly ask yourself if you are not tempted to sneak around the outside, over the top, next to it – instead of going down to the bottom. Every cowardice that does this punishes us by making life more unbearable and more difficult every day. But going down to the bottom does not mean to be destroyed, to break, to go under, but to submerge. You should go to the bottom in life and then see how life is suddenly so simple." 
In a wonderful way, the tree shows us the tension between breathing in the light and being grounded in the earth. Its main nourishment comes from above, from the light. The sunlight is directed deep into the earth. We as human beings are also in a constant interplay between breathing in light and descending into the depths of the subconscious (the “root system”).
Both poles have something in common: we can neither penetrate nor intervene with the "above" or "below" using our will.
The light is offered to us from "above" as a gift; we can only open ourselves to it. Every effort, every deliberate action, would hinder this beam of light. It is similar at the other pole. Images, old wounds, and injuries arise from the subconscious. Here is stored all the layers of consciousness from previous incarnations, all the old wounds, from the "primal wound" to specifically experienced individual wounds and scabs. These scabs and wounds want to be dissolved, redeemed, perceived. However, this cannot happen wilfully and strategically. If we wanted to design a "plan" to dissolve these wounds – and among them, the collective and individual primordial wound –, we would get hopelessly lost. Immense pain from the many injuries would completely overwhelm us and we ould not be able to bearor process it.
Therefore, we must sacrifice our own self-will, through a "dying process" – similar to Odin. "Blood" and "water" must drip from the primal wound as a sign of our inner purification.
 Joachim-Ernst Berendt, Es gibt keinen Weg. Nur Gehen (There is no way. Only Walking), Frankfurt/M. 1999
 Rainer Kiedrowski, Bäume dieser Welt (Trees of this World), Augsburg 2000
 Jan van Rijckenborgh, The Coming New Man, Haarlem (5th edition) 2006
 Wilhelm Engelhardt (teacher and cantor, 1857-1935), Aphorismensammlung (Aphorism collection), https://www.aphorismen.de