Did the author succeed in creating fear and suspense through the girl's journey through the woods?

The fear and suspense is a direct result of Sylvia's reaction to the whistle and the boy's presence in the woods.... something out of the ordinary in the place where she feels most comfortable... the woods. The atmosphere also creates suspense, as she is rarely in the woods when darkness begins to set in.

She was not often in the woods so late as this, and it made her feel as if she were a part of the gray shadows and the moving leaves.

Suddenly this little woods-girl is horror-stricken to hear a clear whistle not very far away. Not a bird’s-whistle, which would have a sort of friendliness, but a boy’s whistle, determined, and somewhat aggressive.