Firemaking

Firemaking is the skill primarily used to light fires but is also a requirement for cannons, collecting guano, charcoal and creating black powder.

Logs
Different logs require different levels to light, with the chance of success also increasing with each level gained. Fires also stay lit longer with better logs and higher levels.

Blackpowder
Blackpowder is used in cannons and various explosive items and processes in the game. It is created by combining charcoal with guano, both which have a firemaking requirement.

Guano
Guano is found in the form of avian or bat excreta across the map, usually on islands, mountain tops in caves. It requires level 35 firemaking and a knife to collect. To harvest guano, the player must right click the block with the knife in hand. Guano re-spawns over time.

Charcoal
Charcoal can be created from logs by burning them at a regular furnace or it can be collected from soot piles left by fires that burn out naturally.

Charcoal from Furnaces
To create charcoal at a furnace, they player needs to right click with a log in hand on the furnace. The amount of experience and charcoal received depends on the top of log as listed below:

Charcoal from Soot
Charcoal can be collected from soot piles by players at any level and is not restricted to the player that lit the original fire. However the fire must have been left to burn out naturally and not have been extinguished. To collect the charcoal, right click on the pile with a knife in hand.