The term biochar was originally associated with a specific type of production, known as ‘slow pyrolysis’. In this type of pyrolysis, oxygen is absent, heating rates are relatively slow, and peak temperatures relatively low (Section 2.1.3.1). However, the term biochar has since been extended to products of short duration pyrolysis at higher temperatures known as ‘fast pyrolysis’ (Section 2.1.3.2) and novel techniques such as microwave conversion.