YGGDRASIL

Celestial Plane

Forgotten Realms

Yggdrasil, also known as the "World Ash", was a cosmic plane-spanning tree that linked the PRIME MATERIAL PLANE through the ASTRAL SEA to the Outer Planes that were important to the Norse pantheon.
"Down the tree is easy; back up is hard."
Yggdrasil was a silver-barked ash tree. Its leaves were blue-black and oval shaped and its rough bark resembled flaking gray clay. It was made of a type of divine wood that was immune to fire, although fallen branches and leaves could be safely used for cooking fires. Spiraling along the main trunk, planks and sets of steps were carved or mounted onto the tree to facilitate traffic. The tree was surrounded by sky in all directions. It produced seeds, but they were known to be sterile by the elven inhabitants of ARBOREA.