A Swedish torch[a] is a source of heat and light from a vertically set tree trunk, incised and burning in the middle.
Oral tradition attributes the development of the torch to the Swedish military during the Thirty Years' War; using a saw or hacksaw or an axe, the Swedes are said to have made burning and glowing logs to warm their soldiers.
[1] This method of providing heat meant that their troops did not have to carry their own firewood with them but were able to get supplies on site, as the freshly cut, green wood can burn due to the chimney effect.
The best types for cooking are hardwoods like beech, oak, apple, ash or cherry, as they are less sooty and would not taint the meat.
[1] The log is easiest to ignite with paraffin (or lighter fluid), which is inserted into the side slots and also at the top at the saw cut point of the trunk.
[1] Choosing a safe place to set the torch is important due to flying sparks and possibility of it falling apart.
It is ignited by pouring a few embers or by loading it with an easily flammable material such as kerosene, fuel tablets, or fire starters.