From Bulbapedia, the community-driven Pokémon encyclopedia.
Healing Forest (Japanese: いやしのもり Healing Forest) is a Friend Area in Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team that is automatically bestowed on the player after adding Celebi to their team. It is in the Western Forest area, and has the capacity of only one Pokémon.
Healing Forest is an average-looking forest clearing. Sunlight streams into the area from above and gives it a peaceful, yet secluded, feel, and one lone particularly large tree stands in the approximate middle of the clearing.
An ethereally beautiful forest. The guardian of forests is said to be here.