Charcoal production (charcoal pile)
A charcoal pile is a large kiln-like structure made from logs and covered with earth, mud and/or manure with the purpose of turning the logs into tar and charcoal.
Charcoal burns almost smokeless, is low in odour and creates high temperatures making it ideal for various uses in prehistoric life and craft.
Charcoal occurs when wood (either freshly chopped or logs that have been in short term storage) is heated up slowly, with an absence of oxygen – a thermo-chemical procedure known as pyrolysis.
The process produces water, gases and tar and leaves behind a carbonized solid residue, char.
The charcoal pile is one of the simplest methods in creating charcoal. A shallow pit, often a few meters in diameter, is dug into the ground with logs carefully stacked forming a mound. This is then completely covered with earth/manure, and sometimes the turf removed to create the pit.
This mound of logs can be lit in different ways to gain the end result of charcoal. One possibility is to light the logs and allow limited oxygen into the mound so that nearby logs carbonize.
Another possibility is to place burning coal at the bottom, prior to stacking the wood, and allowing that to slowly burn the surrounding logs.
The most important factor with producing charcoal is to ensure the wood pile is kept smoldering as opposed to burning the pile with flames. Depending on the size of the log pile, it can often take as little time as 24 hours before charcoal is produced.
For one tonne of charcoal to be produced, 7-9 tonnes of wood would be required for burning. Because the production of charcoal requires a lot of wood, trees can be coppiced (cut down to a certain height to enable multiple re-growths from the tree trunk) which results in many new branches which are often a thickness that would not require sawing or splitting, therefore, an area of coppiced forest could produce a lot more firewood than a forest not managed.