The Gunungan (from gunung = ‘mountain’), also called Kayonan (from kayon = ‘forest’) represents both the Cosmic Mountain (Mount Meru) and the Javanese Tree of Life (Pohon Kahuripan, or Kalpavriksha), the trunk of which forms a passageway between the seen and the unseen worlds (sekala and niskala). It is a symbol of spiritual realization in Javanese culture.

source: https://medium.com/@Kalpavriksha/gunungan-the-javanese-cosmic-mountain-b755e8efa7b5