Biomass

Ecology. the amount of living matter in a given habitat, expressed either as the weight of organisms per unit area or as the volume of organisms per unit volume of habitat.
Energy. organic matter, especially plant matter, that can be converted to fuel and is therefore regarded as a potential energy source.
Contemporary Examples

Dominion Completes Conversion of Coal Plant to Biomass in Virginia William O’Connor July 18, 2013
Dominion Completes Conversion of Coal Plant to Biomass in Virginia William O’Connor July 18, 2013
Palin vs. the Planet Edward Markey July 16, 2009

Historical Examples

Field Study of Kansas Ant-Eating Frog Henry S. Fitch

noun
the total number of living organisms in a given area, expressed in terms of living or dry weight per unit area
vegetable matter used as a source of energy
n.
biomass
(bī’ō-mās’)

Our Living Language : When biologist J.B.S. Haldane was once asked if the study of life on Earth gave him any insights into God, he replied jokingly that his research revealed that God must have “an inordinate fondness for beetles.” Haldane’s comment is based on the fact that there are more beetle species—almost 400,000 now known—than any other animal species. Beetles are just a fragment of the Earth’s biomass, the matter that makes up the Earth’s living organisms. Insects alone—which comprise almost one million known species and perhaps millions yet to be discovered—create an amazing amount of biomass. The number of individual insects is about 10 quintillion (10,000,000,000,000,000,000). Insects probably have more biomass than any other type of land animal. In comparison, if the weight of the Earth’s human population were added up, the biomass of the insect population would be 300 times as great. Biomass also refers to the organic material on Earth that has stored sunlight in the form of chemical energy. Biomass fuels, including wood, wood waste, straw, manure, sugar cane, and many other byproducts from a variety of agricultural processes, continue to be a major source of energy in much of the developing world. There are many who advocate the use of biomass for energy as it is readily available, whereas fossil fuels, such as petroleum, coal, or natural gas, take millions of years to form in the Earth and are finite and subject to depletion as they are consumed.

Note: The term biomass is most often encountered in discussions of sources of energy, as biomass can be used to supply energy needs directly (as fuel wood, for example) or indirectly (by being converted to alcohol; see gasohol).

Biological Investigations of Marine Antarctic Systems and Stocks