In that context, charcoal can be made by numerous and varied methods, from the simplest (an earth cover on the pile of wood, with strategically-placed vents) to the most sophisticated (a modern plant that recuperates and recycles strictly all exhaust gases). The article on biomass explains a few of these methods, as well as the advantages
Slash-and-char offers considerable benefits to the environment when compared to slash-and-burn.
It results in the creation of biochar, which can then be mixed with biomass such as crop residues, food waste, manure and / or other, and buried in the soil to bring about the formation of terra preta. Terra preta is one of the richest soils on the planet - and the only one known to regenerate itself although how this happens precisely is hotly debated within the scientific community.
It moreover sequesters considerable quantities of carbon in the safest and most beneficial fashion, as opposite to the negative effects of the slash-and-burn. Switching to slash-and-char can sequester up to 50% of the carbon in a highly stable form. The nascent carbon trading market that sponsors CO2 sequestration projects, could therefore help supplement the farmers' income while supporting a decrease in the pace of deforestation and the development of a more sustainable agriculture.