The organic component of soil formed by the decay of leaves, wood, and other animal and vegetable matter; the condition of humus affects the spread of a wildland fire
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}