Cursed willow logs are logs obtained from cutting cursed willow roots used in the Summer's End quest. The roots can be found within the caves north of the Abandoned Farm in the Wilderness. To access the caves, players must use Jennica's ring to go into the Spirit Realm through the spiritual portal located within the farm. At the end of the quest, the cave is resealed and will need to be re-opened (this mechanism also gives or removes access to the Corporeal Beast in the physical realm).
Each log cut grants 15 Woodcutting experience, and burning the logs grants the same experience as regular willow logs, 90 Firemaking experience, and produces a white flame. Burning five of them in one of the fire pits in the room where they are cut gives 60 Firemaking experience per log, for a total of 300 for 5 logs. The logs cannot be banked or carried by a Beast of Burden.
As the logs must be added to the fire pit one at a time, this is not a recommended method for training either Woodcutting and Firemaking.
Using these logs on a beacon gives the message "You must have 20 or more of the same type of log which you have the Firemaking level to burn." even if the player has 20 or more.