Long ago, these woods were the lair of a foul lich. Adventurers took care of the lich, but the effects it had on the local plant life remain. Some new growth has come in since the lich's passing, and animals are beginning to re-enter the region, but the dead trees still stand as an ominous reminder of what occurred there.
Because of the abundance of dead wood, the woods have become a particularly abundant habitat for mushrooms and other creatures that thrive on rot. Squeamish creatures prefer to avoid the area, but it is not, in fact, an especially dangerous one.
However, if someone is asked if they mind centipedes prior to an excursion, that question should be taken exceptionally seriously.