Charcoal is a form of recalcitrant carbon, which means that it is very slow to decompose in soils. While recalcitrant carbon is not in a form for microorganisms to process, the physical structure of charcoal absorbs more plant available carbon, called labile carbon. As recalcitrant carbon, biochar is a form of carbon storage, keeping it out of the atmosphere. For every pound of biochar you put in the soil, you keep 2.93 pounds of carbon dioxide from the atmosphere. Let's put carbon in the soil, not the air.