When carbon is oxidized to CO2, a great deal of energy is released as heat. For example, if a gram of glucose molecules is dissimilated under aerobic conditions, 484 to 674 kilogram calories (kcal) of heat may be released. If organic material is in a large enough pile or arranged to provide some insulation, temperatures during decomposition may rise to over 170° F. At temperatures above 160° F, however, the bacterial activity decreases.