if you find a tree that opens mouth when you throw a corpse near it,throw a futrid corpse
or a other enemy in to its mouth and then u will reveal a hint ;)

There are 3 Trees, one at the beginning of Living Forest, one in the second area of Living
Forest, and the last near to the enterence of Reptile's Lair and the saving port. Throw an
enemy into each of these trees' mouths and it will reveal a hint to you for each tree.