The evidence for tree-worship is almost unmanageably large. Trees have played an important role in many of the world’s mythologies and religions, and have been given deep and sacred meanings throughout the ages. Human beings, observing the growth and death of trees, the elasticity of their branches, the sensitivity and the annual decay and revival of their foliage, see them as powerful symbols of growth, decay and resurrection. The most ancient cross-cultural symbolic representation of the universe’s construction is the world tree.
Examples include the Yggdrasil in Norse mythology, the Egyptian Sycamore sitting on the threshold between life and death, and the Kabbalah Tree of Life. There is no doubt that the icon reaches down to the psyche of human beings with its figure of branches reaching towards heavens but with roots deeply grounded on Earth.
“Hail, thou Sycamore Tree of the Goddess Nuit! Give me of the water and of the air which is in thee…“ -Egyptian Book of the Dead
The tree, with its branches reaching up into the sky, and roots deep into the earth, can be seen to dwell in three worlds - a link between heaven, the earth, and the underworld, uniting above and below. It is also both a feminine symbol, bearing sustenance; and a masculine, phallic symbol - another union.
For this reason, many mythologies around the world have the concept of the World tree, a great tree that acts as an Axis mundi, supporting or holding up the cosmos, and providing a link between the heavens, earth and underworld.
The world tree is also a central part of Mesoamerican mythologies, where it represents the four cardinal directions. Other examples of trees featured in mythology are the Banyan and the Peepal (Ficus religiosa) trees in Hinduism, and the modern tradition of the Christmas Tree in Germanic mythology, the Tree of Knowledge of Judaism and Christianity, and the Bodhi tree in Buddhism. In folk religion and folklore, trees are often said to be the homes of tree spirits. Historical Druidism as well as Germanic paganism appear to have involved cultic practice in sacred groves, especially the oak. The term druid itself possibly derives from the Celtic word for oak.