Spiritwood has its own cave system in the mountains east of Skara Brae, the Spirit Tunnels. While tempting with its treasures, it is a horrible trap. Many Ghosts haunt these tunnels, and it is filled with the remains of the unlucky ones whose greed had overcome their common sense, their spirits becoming a part of the horde of ghosts haunting the tunnels. Thus the trap becomes even deadlier with each greedy soul entering them.
Any wise traveler is smart enough to avoid the Spirit Tunnels.
For a solution to the problem, see: Spirit Tunnels Solution