Forbidden Forest

The Forbidden Forest is a location in the Smurf Forest that is scheduled to appear in the upcoming 2017 movie, Smurfs: The Lost Village.

Mainstream Smurfs Media
The forest is set to appear in the upcoming movie, Smurfs: The Lost Village, and can only be reached by traversing through a series of dark caverns with very little light. During the movie's story, Brainy, Clumsy, Hefty and Smurfette traverse through the caverns in search of the Lost Village after Smurfette found a map leading to its location after it was dropped by its mysterious owner.

Hero: The Guardian Smurf stories
Though the forest itself hasn't appeared in any story as-of-yet, there have been rumors going around the village about a part of the forest that homes many strange creatures. In the mini-story, "Dreamy's Dream Preview", Dreamy had a dream about a possible lost village located within the forest and decided to show it to Hero, Wonder and Smurfette in the Imaginarium.