A backyard haunted forest can only come alive if you put a real scare into visitors. You can spend a lot of money to get tricks and treats from haunted house stores, but there are plenty of scary effects that can be made from things around the house or with a much smaller investment.
The Pile Man
Cover a large piece of green fabric with glued or stapled leaves. Gather some leaves into a pile somewhere in your haunted forest and have someone dressed in dark clothing lie down on it. Cover him with the blanket. Tell him to listen for oncoming visitors and to leap out with his scariest cry when they are near.
Aromatic Effects
Hide some Limburger cheese at various points around the forest, then give your haunted forest a back story by announcing that it was the site of several gruesome deaths. Tell visitors that the smell of rotted flesh still lingers in the air. To make it scarier, hide some of the cheese in fake arms and legs from a Halloween store.
The Boneyard
Put some hard pretzel sticks--long and short--beneath an old rug placed strategically in your forest. Then tell your guests to be careful where they walk--the bones of the dead are still scattered about. When they cross over the rug, it will sound like they're crushing old bones.