biomass the organic, non-fossil material of biological origin, a part of which constitutes an exploitable energy resource GRM: n. Note: although the different forms of energy from biomass are always considered as renewable, it must be noted that their rates of renewability are different; these rates depend on the seasonal or daily cycles of solar flux, the vagaries of climate, agricultural techniques or cycles of plant growth, and may be affected by intensive exploitation; however, as a statistical average, they may be considered as renewable yearly (1); it may be the total quantity, at a given time, of living organisms of one or more species per unit area (species biomass) or of all the species in a community (community biomass) (2)