Camping out in the forest, or even the backyard, has a long history in the modern world. Entertainment generally consists of talking around a bright campfire during the darkness, and generations of families have done this as a favorite summertime entertainment. Sharing oral histories or conversation is nice, but the surrounding darkness and isolation are the perfect background to share ghost stories. It is the setting itself that lends credence to the spoken word.
Part of the pleasure of camping out is getting away from modern life, and that means no electric lights or conveniences. When the sun goes down, darkness changes the area into an unexplored realm where anything might live. Once this happens, it is the best time to light the fire and huddle together in a group. The crackle of knots burning, the smoke traveling up to the stars and the night noises all contribute to the atmosphere necessary to make ghost stories believable.
Telling children ghost stories has often been a favorite occupation of adults and older siblings, and they use the glow of the fire to measure their success. They start out in a normal tone of voice, but they begin to tone it down and become quieter as their audience falls into the tale. As the younger children lean forward to hear more, they know they have caught them up in the realism they are trying to create.
Not all ghost stories are scary, but the ones told around campfires tend to be those that give a good shock or small fright to their audiences. This is generally accomplished with the storyteller making their audience imagine a long dead visitor is approaching. Yelling that the ghost is right there at the end makes everyone jump, and it completes the story that may haunt them for years.