The Girl and the Guardian
CHAPTER 21. The manner of feeding the Mother Thorn was this: the travellers would go out and find any dead animals, and later, growing more cunning, also live animals, and they would bear them back to the Mother Thorn, and impale them on her thorn-points. She would then suck the juices from them, and the remains would fertilise the ground below, where her roots would use up the remainder. And in later times, the thorns came to have the power to drug and preserve alive their victims, and this is the origin of the Avenue of Despair: The Thornmen arranged with the Mother Thorn to not devour some they wanted to be displayed as a warning, but preserve them indefinitely in a living death.
In return the Mother Thorn would keep an open space within her branches where the Thornmen rested, protected from their enemies; and she would feed them from her sap.
All of the sons of one thorn had the power of communication in dreams with one another, and they would come to each other’s aid if in need, or return to the Mother Thorn if she was threatened. Some say they also heard the voice of their mother, speaking in the depths of their being. -Ennead, of the Thornmen.