Biochar ovens are low tech biochar production units with a primary design function of producing biochar. This category of biochar production unit can be suitable for clean, healthy, distributed low tech biochar production (DLT) of by developing country smallholders and micro-entrepreneurs; “backyard” producers utilizing yard waste; small and urban farmers; nurseries; communal gardens; etc to convert the thinly distributed feedstock (TDF) available to them. The feedstock ‘chamber’ of these units will usually be in the range of very small to 4-500 liters. The primary functional design of these units is to produce biochar. To date, the primary technologies used in units that fall within this category are retorts; Top Lit Up Draft (TLUD) units and TLUD/retort hybrids; and Top Fed Open Draft (TFOD) units such as cones and pyramids (metal & pit) and rings. Other functional designs may fall within this category (based on size, primary design function, and technology level) as they are developed. The name of this category is based on the metaphor that, as a bread oven is a unit used to bake dough to produce bread, a biochar oven is unit used to bake feedstock to produce biochar.