Dryads and Hamadryads are two types of wood nymphs.
They are female nature spirits were thought to inhabit trees and forests, and they were especially fond of oak trees.

Dryads can be found in the secluded places such as oak trees. They are very shy and non-violent so they are never more than a few feet away from their individual tree. Unless they are surprised, dryads can disappear by stepping into a tree.