A hamadryad is a Greek mythological being that lives in trees. They are a particular type of dryad, which are a particular type of nymph. Hamadryads are born bonded to a certain tree. Some believe that hamadryads are the actual tree, while normal dryads are simply the entities, or spirits, of the trees. If the tree died, the hamadryad associated with it died as well. For that reason, dryads and the gods punished any mortals who harmed trees.