The mysterious, out of the way clearing in the forest is a tradition as old as Greek mythology itself. Here's a tip: don't ever go into the mysterious clearing in the forest. Why? Think about it: Where is the witch's house in Hansel and Gretel? Mysterious clearing in the forest. Where does Red Riding Hood meet the wolf? In the forest. Where does Narcissus catch sight of his reflection and starve to death? Forest.
Bottom line: if you ever find yourself in a fairytale or mythological story, stay out of forests. They're bad. Authors actually use the mysterious clearing to alert readers that something fishy is about to happen. The setting actually becomes a subtle kind of what scholars call foreshadowing: the moment that a character stumbles on a clearing, we know something's wrong. And this is exactly what happens in the story of Echo and Narcissus. Nicely done, mythology, nicely done.