Estimation approaches involve techniques that require observers to visually assess biomass in quadrats, rather than harvesting to determine biomass. Three common estimation methods to determine biomass are commonly used:
Binomial distributions are special sampling distributions generated when an attribute with only two possible outcomes is being recorded from a series of sample units. The sample units should be independent and selected by random sampling.
Animal units (AU) are used as a basis to standardize and express stocking rates among different kinds and classes of livestock with similar dietary preferences. An AU is essentially a measure of forage demand by a theoretical animal unit that can then be converted according to the relative demands of different animal classes (based primarily on metabolic bodyweight) (Table 1).
Allowable use, or proper use, refers to the level of utilization that promotes maximum grazing of forage sources without damaging the vegetation. Allowable use may refer to the entire management unit; or it may be based on selected key species.
Sample units are the members of the population from which measurements are taken during sampling. Sample units are distinct and non-overlapping entities, such as quadrats or transects, individual plants, branches within a plant, etc.
Sample size, or sampling intensity, refers to the number of sample units that will be measured in the inventory or monitoring program.