Animal-Unit-Equivalent. A number expressing the energy requirements of a particular kind or class of animal relative to one AU. Abbr. AUE.

Animal-Unit-Month. The amount of dry forage required by one animal unit for one month based on a forage allowance of 26 pounds per day. Not synonymous with animal-month. Abbr. AUM. The term AUM is commonly used in three ways: (a) Stocking rate, as in "X acres per AUM"; (b) forage allocations, as in "X AUMs in Allotment A"; (c) utilization, as in "X AUMs taken from Unit B."

Annual Plant. A plant that completes its life cycle and dies in 1 year or less.

Available Forage. That portion of the forage production that is accessible for use by a specified kind or class of grazing animal.

Backfiring. Ignition of a fire on the leeward (downwind) side of a burn area, resulting in a slow moving ground fire. cf. headfiring.

Biomass. The total amount of living plants and animals above and below ground in an area at a given time.

Browse. (n.) That part of leaf and twig growth of shrubs, woody vines and trees available for animal consumption. (v.) Act of consuming browse. cf. graze.

Brush. A term encompassing various species of shrubs or small trees usually considered undesirable for livestock or timber management. The same species may have value for browse, wildlife habitat, or watershed protection.

Brush Control. Reduction of unwanted woody plants through fire, chemicals, mechanical methods, or biological means to achieve desired land management goals.

Brush Management. Manipulating woody plant cover to obtain desired quantities and types of woody cover and/or to reduce competition with herbaceous understory vegetation, in accordance with ecologically sound resource management objectives.

Bunch Grass. A grass having the characteristic growth habit of forming a bunch; lacking stolens or rhizomes, cf. sod grass.

Burn. An area over which fire has recently passed.

C-3 Plant. A plant employing the pentose phosphate pathway of carbon dioxide assimilation during photosynthesis; often a cool-season plant.

C-4 Plant. A plant employing the dicarboxylic acid pathway of carbon dioxide assimilation during photosynthesis; often a warm-season plant.

Carrying Capacity. The maximum stocking rate possible which is consistent with maintaining or improving vegetation or related resources. It may vary from year to year on the same area due to fluctuating forage production. cf. grazing capacity.

Cell. A grazing arrangement comprised of numerous sub-divisions (paddocks or pastures) often formed by electrical fencing, with a central component to facilitate livestock management and movement to the various sub-divisions. Normally used to facilitate a form of controlled grazing. cf. paddock.

Class of Animal. Description of age and/or sex-group for a particular kind of animal. Example, cow, calf, yearling, ewe, doe, fawn, etc.

Climax. (1) The final or stable biotic community in a successional series which is self-perpetuating and in dynamic equilibrium with the physical habitat; (2) the assumed end point in succession, cf. potential natural community.

Complementary Pasture. Short-term forage crop (not necessarily annual) planted for use by domestic stock to enhance the management and productivity of the ranch.

Continuous Grazing. The grazing of a specific unit by livestock throughout a year or for that part of the year during which grazing is feasible. The term is not necessarily synonymous with yearlong grazing, since seasonal grazing may be involved.

Cool-Season Plant. A plant which generally makes the major portion of its growth during the late fall, winter, and early spring. Cool-season species generally exhibit the C3 photosynthetic pathway. cf. warm-season plant.

Cultivar (derived from cultivated variety). A named variety selected within a plant species. Distinguished by any morphological, physiological, cytological, or chemical characteristics. A variety of plant produced and maintained by cultivation which is genetically retained through subsequent generations.

Decreaser. Plant species of the original or climax vegetation that will decrease in relative amount with continued disturbance to the norm, eg., heavy defoliation, fire, drought. Some agencies use this only in relation to response to overgrazing.

Deferment. Delay of livestock grazing on an area for an adequate period of time to provide for plant reproduction, establishment of new plants, or restoration of vigor of existing plants. cf. deferred grazing, rest.

Deferred Grazing. The use of deferment in grazing management of a management unit, but not in a systematic rotation including other units. cf. grazing system.

Deferred-Rotation. Any grazing system, which provides for a systematic rotation of the deferment among pastures.

Defoliation. The removal of plant leaves, i.e., by grazing or browsing, cutting, chemical defoliant, or natural phenomena such as hail, fire, or frost.

Degree of Use. The proportion of current year's forage production that is consumed and/or destroyed by grazing animals. May refer either to a single species or to the vegetation as a whole. Syn. use.

Drouth (Drought). (1) A prolonged chronic shortage of water, as compared to the norm, often associated with high temperatures and winds during spring, summer, and fall. (2) A period without precipitation during which the soil water content is reduced to such an extent that plants suffer from lack of water.

Ecology. The study of the interrelationships of organisms with their environment.

Ecosystem. Organisms together with their abiotic environment, forming an interacting system, inhabiting an identifiable space.

Ecotype. A locally adapted population within a species which has certain genetically determined characteristics; interbreeding between ecotypes is not restricted. cf. biotype.

Environment. The sum of all external conditions that affect an organism or community to influence its development or existence.

Esophageal-Cannula. A device used for maintenance and closure of an esophageal fistula.

Esophageal-Fistula. A permanent, surgically established opening in the esophagus of an animal used for collecting diet samples. cf. Esophageal-cannula.

Firebreak. A natural or man-made barrier used to prevent or retard the spread of fire, that is in existence or made before a fire occurs. It is usually created by the removal of vegetation. cf. fireline, fuelbreak.

Forage. (n.) Browse and herbage which is available and may provide food for grazing animals or be harvested for feeding. cf. concentrate feed and cured and range forage. (v.) To search for or consume forage. Syn. graze.

Forage Production. The weight of forage that is produced within a designated period of time on a given area. The weight may be expressed as either green, air-dry, or oven-dry. The term may also be modified as to time of production such as annual, current year's, or seasonal forage production.

Forb. Any broad-leafed herbaceous plant other than those in the Gramineae (or Poaceae), Cyperaceae and Juncacea families.

Frequency. The ratio between the number of sample units that contain a species and the total number of sample units.

Fresh Mulch. The primary layer of bulky, coarse, largely undecayed herbage residuum. cf. mulch and humic mulch.

Grasslike Plant. A plant of the Cyperaceae or Juncaceae families which vegetatively resembles a true grass of the Gramineae family.

Graze. (1) (vi.) The consumption of standing forage by livestock or wildlife. (2) (vt.) To put livestock to feed on standing forage.

Grazing Behavior. The forageing response elicited from a herbivore by its interaction with its surrounding environment.

Grazing Capacity. The total number of animals which may be sustained on a given area based on total forage resources available, including harvested roughages and concentrates. cf., carrying capacity.

Grazing Management. The manipulation of grazing and browsing animals to accomplish a desired result.

Herbaceous. Vegetative growth with little or no woody component. Non-woody vegetation, such as graminoids and forbs.

Herbage. (1) Herbs taken collectively. (2) Total aboveground biomass of herbaceous plants regardless of grazing preference of availability.

Herbivore. An animal that subsists principally or entirely on plants or plant materials.

Holistic Resource Management. Holistic Resource Management (HRM) is a practical, goal-oriented approach to the management of the ecosystem including the human, financial and biological resources on farms, ranches, public and tribal lands, as well as national parks, vital water catchments and other areas. HRM entails the use of a management model which incorporates a holistic view of land, people and dollars.

Increaser. Plant species of the original vegetation that increase in relative amount, at least for a time, under continued disturbance to the norm, e.g., heavy defoliation, fire, drought.

Invader. Plant species that were absent in undisturbed portions of the original vegetation of a specific range site and will invade or increase following disturbance or continued heavy grazing.

Key Species. (1) Forage species of sufficient abundance and palatability to justify its use as an indicator to the degree of use of associated species. (2) Those species which must, because of their importance, be considered in the management program.

Marsh. Flat, wet treeless areas usually covered by standing water and supporting a native growth of grasses and grasslike plants.

Moderate Grazing. A comparative term which indicates that the stocking rate of a pasture is between the rates of other pastures. Often erroneously used to mean proper use. cf. heavy and light grazing.

Multiple Use. Use of range for more than one purpose, i.e., grazing of livestock, wildlife production, recreation, watershed and timber production. Not necessarily the combination of uses that will yield the highest economic return or greatest unit output. Syn. multiple land use.

Native Species. A species which is a part of the original fauna or flora of the area in question. Syn. indigenous. cf. introduced and resident species.

Non-Selective Grazing. utilization of forage by grazing animals in such a way that all forage species and plants are grazed to a comparable degree. It is generally achieved by using a high stocking density for a short grazing period.

Oven-Dry Weight. The weight of a substance after it has been dried in an oven at a specific temperature to equilibrium.

Overgrazing. Continued heavy grazing which exceeds the recovery capacity of the community and creates a deteriorated range. db. overuse.

Overstocking. Placing a number of animals on a given area that will result in overuse if continued to the end of the planned grazing period.

Palatability. The relish with which a particular species or plant part is consumed by an animal.

Percent Use. Grazing use of current growth, usually expressed as a percent of the current growth (by weight) which has been removed. cf. degree of use.

Perennial Plant. A plant that has a life span of 3 or more years.

Phenology. The study of periodic biological phenomena which are recurrent such as flowering, seeding, etc., especially as related to climate.

Plant Vigor. Plant health. cf. plant vigor index.

Preferred Species. Species that are preferred by animals and are grazed by first choice.

Prescribed Burning. The use of fire as a management tool under specified conditions for burning a predetermined area. cf. maintenance burning.

Pristine. A state of ecological stability or condition existing in the absence of direct disturbance by modern man.

Proper Grazing. The act of continuously obtaining proper use.

Range. (n.) Any land supporting vegetation suitable for grazing including rangeland, grazable woodland and shrubland. Range is not a use. (adj.) Modifies resources, products, activities, practices, and phenomena pertaining to rangeland, cf. rangeland, forested range, grazable woodland, shrubland.

Range Condition. (a) A generic term relating to present status of a unit of range in terms of specific values or potentials. Specific values or potentials must be stated. (b) Some agencies define range condition as follows: The present state of vegetation of a range site in relation to the climax (natural potential) plant community for that site. It is an expression of the relative degree to which the kinds, proportions, and amounts of plants in a plant community resemble that of the climax plant community for the site. cf. ecological status and resource value rating.

Range Condition Class. Confusion has existed regarding both definition and use of this term. (1) The following definition fits the thinking expressed in the definition Range Condition (a) above: One of a series of arbitrary categories used to either classify ecological status of a specific range site in relation to its potential (early, mid, late seral or PNC) or classify management-oriented value categories for specific potential, eg., good condition spring cattle range. (2) Some agencies consider range condition class in the context of Range Condition (b) above as follows:

Range Improvement. (1) Any structure or excavation to facilitate management of range or livestock. (2) Any practice designed to improve range condition or facilitate more efficient utilization of the range. (3) An increase in the grazing capacity of range, i.e., improvement of rangeland condition.

Range Management. A distinct discipline founded on ecological principles and dealing with the use of rangelands and range resources for a variety or purposes. These purposes include use as watersheds, wildlife habitat, grazing by livestock, recreation, and aesthetics, as well as other associated uses.

Range Site. Synonymous with ecological site when referring to rangeland. An area of rangeland which has the potential to produce and sustain distinctive kinds and amounts of vegetation to result in a characteristic plant community under its particular combination of environmental factors, particularly climate, soils, and associated native biota. Some agencies use range site based on the climax concept, not potential natural community. cf. vegetation type.

Rest. Leaving an area ungrazed thereby foregoing grazing of one forage crop. Normally rest implies absence of grazing for a full growing season or during a critical portion of plant development; i.e., seed production. cf. deferment.

Rhizome. A horizontal underground stem, usually sending out roots and above-ground shoots from the nodes.

Rotation Grazing. A grazing scheme where animals are moved from one grazing unit (paddock) in the same group of grazing units to another without regard to specific graze:rest periods or levels of plant defoliation. cf. grazing system.

Roughage. Plant materials containing a low proportion of nutrients per unit of weight and usually bulky and coarse, high in fiber and low in total digestible nutrients. Roughage may be classed as either dry or green.

Short-Duration Grazing. Grazing management whereby relatively short periods (days) of grazing and associated non-grazing are applied to range or pasture units. Periods of grazing and non-grazing are based upon plant growth characteristics. Short duration grazing has nothing to do with intensity of grazing use. cf. grazing system.

Shrub. A plant that has persistent, woody stems and a relatively low growth habit, and that generally produces several basal shoots instead of a single bole. It differs from a tree by its low stature (generally less than 5 meters, or 16 feet) and non-arborescent form.

Stocking Density. The relationship between number of animals and area of land at any instant of time. It may be expressed as animal-units per acre, animal-units per section or AU/ha. cf. stocking rate.

Stocking Rate. The number of specific kinds and classes of animals grazing or utilizing a unit of land for a specified time period. May be expressed as animal unit months or animal unit days per acre, hectare, or section, or the reciprocal (area of land/animal unit month or day). When dual use is practiced (eg., cattle and sheep), stocking rate is often expressed as animal unit months/unit of land or the reciprocal. Syn. stocking level, cf. stocking density.

Trend (Range Trend) Classes and Ecological Status Ratings. Trend in range condition or ecological status should be described as up, down or not apparent. Up represents a change toward climax or potential natural community; down represents a change away from climax or potential natural community; and not apparent indicates there is no recognizable change. This category is often recorded as static or stable. There is no necessary correlation between trends in resource value ratings, vegetation management status, and trend in range condition or ecological status.

Usable Forage. That portion of the forage that can be grazed without permanent damage to the forage plant species or the other basic resources; may vary with season of use, plant species and associated plant species.

Vegetation. Plants in general, or the sum total of the plant life above and below ground in an area. cf. vegetative.

Vegetative. Relating to nutritive and growth functions of plant life in contrast to sexual reproductive functions. Of or relating to vegetation. cf. vegetation.

Warm-Season Plant. A plant which makes most or all its growth during the spring, summer or fall and is usually dormant in winter. (2) A plant that usually exhibits the C-4 photosynthetic pathway.

Wetlands. Areas characterized by soils that are usually saturated or ponded, i.e., hydric soils, that support mostly water-loving plants (hydrophytic plants).