Tree of Silver

The Tree of Silver was a living, metallic tree that formed shortly after the creation of the World of Narnia. When Andrew Ketterley accidentally stumbled into the empty world that would become Narnia – specifically the area that would later become Lantern Waste – he was carrying several silver coins in his pocket. When the half-crown silver coins fell into the magically imbued soil of the newly created world, they grew into a living tree made entirely of silver.

It is not known how long the Tree of Silver stood in Narnia. By the time of The Last Battle (the only other time it was directly mentioned), it was already gone from Lantern Waste, but stories about it had apparently been passed down through the centuries: King Tirian not only knew of  the tree's existence, but precisely where in the woods of Lantern Waste it had once stood.

Trivia

 * The Tree of Silver, along with it's counterpart, the Tree of Gold might be reference to the Trees of Valinor (golden Laurelin and silver Telperion) that appeared in the works of C.S.Lewis' lifelong friend J.R.R.Tolkien.