From Bulbapedia, the community-driven Pokémon encyclopedia.
Energetic Forest is a Friend Area in Pokémon Mystery Dungeon or from the start if the starter Pokémon is either Pikachu, Meowth, or Skitty, or if Pikachu is chosen as the partner Pokémon. It is available for 5000 Poké from Wigglytuff in Pokémon Square. It is in the Eastern Forest area, and has the capacity of fifteen Pokémon. The starter Pokémon Pikachu, Meowth, and Skitty are kept here.
It is a glade in a forest, with small glowing balls of energy and beams of light hitting the forest floor.
A vibrant area where elemental energy -- the life force for all things -- rises from the earth. Unique Pokémon are found here.