There is a cave at Joshimath in Uttarakhand and it is believed that Adi Shankaracharya mediated and lived in the cave. Near this cave there is a mulberry tree which is known as tree of enlightenment. Locals refer to it as Kaplavriksha and existed since the times of Adi Shankaracharya.
The tree is now very old and is not in a great condition.
But the tree still foliages in the spring time.
Joshimath or Jyotrimath is one of the four maths established by Adi Shankaracharya. The other three are the Sringeri Math in Karnataka, Govardhana Matha in Puri and Sharda Matha in Dwaraka.