This ‘Swedish Fire’ is a self-feeding, one-piece fire unit; an upright log with three downward cuts running nearly its total length. The name comes from the German word "Schwedenfeuer" meaning Sweden Fire Soldiers. During the Thirty Years' War between1618-1648, the Swedish soldiers waging campaigns in the cold winter months in southern Germany kept themselves warm with the Schwedenfeuer.
Your intended use of the Swedish Fire will determine the type of wood to use. We have so many wood types to choose from, all of which have their own burning qualities and properties, but the most important factor is that the wood is dry and well seasoned as it will burn efficiently, providing the most heat and least smoke.
For a candle, hardwood like Birch [Betula], burns quickly and hot, providing an excellent light source. If you want a camp fire or natural stove a native hardwood with lower moisture content such as Oak [Quercus], Ash [Fraxinus] and Hornbeam [Carpinus] provide a larger surface area and burn well giving off plenty heat.