From the introduction:
Role-playing game adventuring parties often find themselves in a forest. Their quests take them through or near or beyond great wooded lands on many occasions. Fill your RPG campaign with mystery and wonder. Don't allow yourself as a GM to simply rely on clichés or to brush past opportunities. Leave a lasting impression on your players. It is easy to throw a few creatures in here or there. Perhaps a few bandits, or other standard encounters and that's it. The party breezes through the forest and there are a few episodes of minor combat. Then the party reaches the temple, the dungeon, the castle, or the town. However, as a serious Game Master you should be looking for ways to give every part of your campaign the chance to live and breathe.
Forests are no exception.