Biomass is a measure of the amount of biological substance minus its water content found at a given time and place on the earth's surface. Although sometimes defined strictly as living material, in actual practice the term often refers to living organisms, or parts of living organisms, as well as waste products or non-decomposed remains. It is a distinguishing feature of ecological systems and is usually presented as biomass density in units of dry weight per unit area. The term is somewhat imprecise in that it includes autotrophic plants, referred to as phytomass, heterotrophic microbes, and animal material, or zoomass. In most settings, phytomass is by far the most important component. A square meter of the planet's land area has, on average, about 22.05 – 26.46 lb (10 – 12 kg) of phytomass, although values may vary widely depending on the type of biome. Tropical rain forests average about 45 kg/m² while a desert...