A bruma root is obtained by chopping bruma roots found in the four corners of the Wintertodt's prison north of the Wintertodt Camp. The experience given is equal to 0.3 times the player's Woodcutting level.
It is used to burn the brazier that is used to drain the Wintertodt's energy, granting Firemaking experience equal to 3x the player's level per log. These can be fletched into bruma kindlings, which give 3.8x the player's Firemaking level in experience, roughly 27% more.
Bruma roots are used in the rituals performed by the Disciples of Yama.