Understanding Biomass?

What is Biomass or Production?

Biomass is the total weight of living organisms, including plants and animals, for a given area usually expressed as kg/ha, lbs/acre, g/m², etc.  For most ecological investigations and for the purposes of this course, "biomass" is a vegetation attribute that refers to the weight of plant material within a given area. Another commonly used term for biomass is "production" which refers to how much vegetation is produced on an area.

The biomass on a site can be estimated by species (i.e., weight of each individual plant species) or biomass can be estimated in groups such as growth form (grass, forb, shrubs, or trees), plant longevity (annual or perennial), or degree of woodiness (herbaceous or woody).

Terms for Biomass

Gross Primary Production = Total amount of organic matter in an ecosystem including above ground (i.e., leaves and stems) and below ground (i.e., roots) biomass. Also sometimes referred to as Net Primary Production.

Residual Biomass = Amount of vegetation remaining after grazing is completed.

Phytomass = Total weight of plant mass per unit of area in an ecosystem.

Standing Crop = The amount of biomass at a given time. Usually refers to the amount of above-ground plant biomass.

Peak Standing Crop = The maximum amount of standing crop observed during a given year.

Forage = Herbage or browse that is accessible and acceptable as food for grazing and browsing animals.

Herbage = Above ground biomass of herbaceous plants.

Browse = The portion or amount of woody plants available for animal consumption. Usually current season’s growth of twigs and leaves.

Mast = Fruits, nuts, and seeds produced by woody plants and used as food by animals.

Necromass = The accumulated dead biomass, or litter.