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	AAC apportionment: the distribution of the AAC for a TSA among timber tenures by the Minister in accordance with Section 10 of the Forest Act.
	Abiotic factors: the non-living components of the environment, such as air, rocks, soil, water, peat, and plant litter.
	Aboriginal resource site/unit: an investigated unit identified by the aboriginal communities/bands that provides resources for food or culture uses (e.g. ceremonies). Each site is described by its band, location and resource type, use and quality on a monthly basis. This information is confidential and not released without a band’s permission.
	Access management plan: An operational plan that shows how road construction, modification and deactivation will be carried out to protect, or mitigate impacts on known resources or sensitive areas while maximizing the efficacy of forest resource development.
	Active floodplain: the level area with alluvial soils adjacent to streams that is flooded by stream water on a periodic basis and is at the same elevation as areas showing evidence of flood channels free of terrestrial vegetation, recently rafted debris or fluvial sediments newly deposited on the surface of the forest floor or suspended on trees or vegetation, or recent scarring of trees by material moved by flood waters.
	Adaptive management: adaptive management rigorously combines management, research, monitoring, and means of changing practices so that credible information is gained and management activities are modified by experience.
	Additive effects: effects on biota of stress imposed by one mechanism, contributed from more than one source (e.g., sediment-related stress on fish imposed by sediment derived from streambank sources and from land surface sources). (see also cumulative effects).
	Administrative law: the branch of the law which deals with the actions of government vis a vis the public.
	Advanced regeneration: trees that have become established naturally under a mature forest canopy and are capable of becoming the next crop after the mature crop is removed.
	Adverse slope: an uphill incline for hauling or skidding of logs or other loads.
	Aerial photography: photos taken from the air at regular, spatial intervals and used in photo interpretation to provide much information about forests and landforms.
	Afforestation: the establishment of trees on an area that has lacked forest cover for a very long time or has never been forested.
	Age class: any interval into which the age range of trees, forests, stands, or forest types is divided for classification. Forest inventories commonly group trees into 20-year age classes.
	Aggradation: accumulation of sediment in a stream channel on an alluvial fan or on a floodplain. Also applied to sediment accumulation on slopes.
	Aggregated retention: retaining trees in patches throughout a cutblock or cutting unit.
	Airtanker: a fixed-wing aircraft fitted with tanks and equipment for dropping suppressants or retardants.
	Alienation: Defined in the Forest Practices Code of British Columbia Act as any land that has had its "right-to-use" transferred from the Crown through grant, lease, or permit or has a special interest noted, as in reserves. Land may be so designated permanently or temporarily.
	All-aged stand: see uneven-aged stand.
	Allowable Annual Cut (AAC): The allowable rate of timber harvest from a specified area of land. The chief forester sets AACs for timber supply areas (TSAs) and tree farm licences (TFLs) in accordance with Section 8 of the Forest Act.
	Amortization: a procedure by which the capital cost of projects, such as roads or bridges, is written off over a specified period of time as the timber volumes developed by the projects are harvested and extracted.
	Anadramous: fish that breed in fresh water but live their adult life in the sea. On the Pacific coast, anadramous fish include all the Pacific salmon, steelhead trout, some cutthroat trout and Dolly Varden char, lampreys and eulachons.
	Analysis unit: the basic building blocks around which inventory data and other information are organized for use in forest planning models. Typically, these involve specific tree species or type groups that are further defined by site class, geographic location or similarity of management regimes.
	Animal Unit Month (AUM): the amount of forage required for one month by an average animal of the genus Bos (i.e., a cow) aged 6 months or older.
	Aquatic habitat: habitat where a variety of marine or freshwater flora and fauna occur for long periods throughout the year. Examples include tide pools, estuaries, bogs, ponds and potential underwater diving areas.
	Archaeological site: a location that contains physical evidence of past human activity and that derives its primary documentary and interpretive information through archaeological research techniques. These resources are generally associated with both the pre-contact and post-contact periods in British Columbia. These resources do not necessarily hold direct associations with living communities.
	Artificial regeneration: establishing a new forest by planting seedlings or by direct seeding (as opposed to natural regeneration).
	Aspect: the direction toward which a slope faces.
	Available timber (see also Operable timber): timber which is available for harvest after due recognition of constraints to protect the environment and other forest uses.
	Available volumes: the portion of total inventory volumes that is available for harvesting after all management constraints on timber harvesting have been considered, including definition of the timber harvesting land base, age of tree merchantability, deferrals and any other priorities or constraints on timber harvesting.
	Average long term yield: the annual average of the total yield over the next 200 years minus unsalvaged losses. This figure is generally greater than the long run sustained yield due to the influence of cutting old growth timber in the first few decades.
	Avoidable waste: the volume of timber left on the harvested area that should have been removed in accordance with the utilization standards in the cutting authority. It does not include the volume of timber that could not be removed because of physical impediments, safety considerations, or other reasons beyond the control of the licensee. Avoidable waste volumes are billed monetarily, as well as for cut control.
	Azimuth: the horizontal angle or bearing of a point measured from the true (astronomic) north. Used to refer to a compass on which the movable dial (used to read direction) is numbered in 360ํ. See: Bearing and Compass.