T

	Target stocking standards: the number of well-spaced acceptable trees per hectare that will, in normal circumstances, produce an optimum free-growing crop; the standards at which silviculture treatments are aimed.
	Temporary access structure: a structure that would be a permanent access structure except that it is not shown on a forest development plan, access management plan, logging plan, road permit or silviculture prescription as remaining operational after the completion of timber harvesting activities.
	Temporary bridge: a bridge having most of its major components constructed of untreated wood.
	Temporary tenures: non-alienated lands on which the timber is alienated to private interests, but where the Crown retains ownership of the lands. These lands include timber licences, timber leases and timber berths as well as pulp licences and pulp berths, including those now in tree farm licences under Schedule "A."
	Tending: any operation carried out for the benefit of a forest crop or an individual thereof, at any stage of its life. It includes operations both on the crop itself and on competing vegetation but not site preparation or regeneration cuttings.
	Tenure: the holding, particularly as to manner or term (i.e., period of time), of a property. Land tenure may be broadly categorized into private lands, federal lands, and provincial Crown lands. The Forest Act defines a number of forestry tenures by which the cutting of timber and other user rights to provincial Crown land are assigned.
	Tenure holder: an individual, group, or company that holds a licence agreement as defined
	Tenure management plan: a plan that relates to the management, development and use, by the holder of a licence or permit granted under the Range Act, of the Crown range to which the licence or permit applies, including the management and use, affecting Crown range, of the following land: to which a licence or permit is made appurtenant, land which is subject to an agreement under section 17 of the Range Act, and unfenced land used for grazing purposes in common with Crown range to which a licence or permit applies.
	Terrain: the physical features of a tract of land.
	Terrain hazard assessment: an assessment or characterization of unstable or potentially unstable slopes on forested lands. A determination of the relative potential of landslide initiation and the type of landslide that may occur on different types of terrain, based on the data obtained from a review of available maps, photos, site data, and field observations.
	Terrain stability risk: a combined assessment of both the likelihood of landslide initiation and an order of magnitude estimate of the amount of landslide debris that might enter a stream or of the potential lengths of scour of a stream by a landslide.
	Thinning: a cutting made in an immature crop or stand primarily to accelerate diameter increment but also, by suitable selection, to improve the average form of the trees that remain.

Threatened or endangered plant communities: ecosystems, as listed by the Conservation Data Center, that:

are restricted in their distribution over a natural landscape (e.g., freshwater wetlands within certain biogeoclimatic) or are restricted to a specific geographic area or a particular type of local environment; or

were previously widespread or common but now occur over a much smaller area due to extensive disturbance or complete destruction by such practices as intensive harvesting or grazing by introduced species, hydro projects, dyking, and agricultural conversion.

Threatened or endangered species: threatened or endangered species as identified by the Ministry of Environment, Lands and Parks. The taxa on the red list are either Extirpated, Endangered or Threatened, or are being considered for such status. Any indigenous taxon (species or sub-species) threatened with imminent extinction or extirpation throughout all or a significant portion of its range in British Columbia is Endangered. Threatened taxa are those indigenous species or sub-species that are likely to become endangered in British Columbia if factors are nor reversed.

Timber: trees, whether standing, fallen, living, dead, limbed, bucked or peeled.

Timber cruising: the collection of field data on forests commonly by the measurement and recording of information in sample plots. Includes the measurement and estimation of volumes of standing trees.

Timber harvesting land base: the portion of the total area of a management unit considered to contribute to, and be available for, long-term timber supply. The harvesting land base is defined by reducing the total land base according to specified management assumptions.

Timber licence: area-based tenures which revert to the government when merchantable timber on the area has been harvested and the land reforested. Many of these licences have been incorporated into tree farm licences.

Timber management prescriptions: recommended forest management practices, usually pertaining to the sub-unit and operational levels of planning.

Timber mark: a hammer indentation made on cut timber for identification purposes.

Timber operability (see also Operable timber): in a planning context, the term refers to the economic suitability of timber for harvesting. Parameters to consider in assessing operability include: terrain, timber quality, timber size, operating season, labour costs, development costs, and transportation costs. In the Environmental Protection Area program, operability refers to freedom from harvesting constraints which include environmental protection and other forest uses.

Timber sale licence: an agreement entered into under Part 3, Division (3) of the Forest Act. A timber sale licence usually defines a specific volume of timber to be harvested from a specific area. In special circumstances, an allowable annual cut (AAC) is specified. Allows the orderly harvest of relatively small volumes of timber by

operators with small cuts;

operators registered under the Small Business Forest Enterprise Program or others with temporary cutting rights; and

holders of pulpwood agreements.

Timber supply: the available timber categorized by species, end-use, and relative value.

Timber supply analysis: an assessment of future timber supplies over long planning horizons (more than 200 years) by using timber supply models for different scenarios identified in the planning process.

Timber Supply Area (TSA): An integrated resource management unit established in accordance with Section 6 of the Forest Act. TSAs were originally defined by an established pattern of wood flow from management units to the primary timber-using industries.

Timber Supply Block (TSB): a division of a timber supply area.

Timber supply model: an analytical model (usually computer-based) that simulates the harvest and growth of collections of forest stands over several decades according to specific data and management assumptions.

Timber utilization: the dimensions and quality of timber that is actually cut and removed from an area.

Tolerance: the ability of an organism or biological process to subsist under a given set of environmental conditions. The range of these under which it can subsist, representing its limits of tolerance, is termed its ecological amplitude. For trees, the tolerance of most practical importance is their ability to grow satisfactorily in the shade of and in competition with other trees.

Top height: the average height of the hundred trees of largest diameter per hectare.

Topographic break: a distinct change in the slope of the land.

Topography: the physical features of a geographic area, such as those represented on a map, taken collectively; especially, the relief and contours of the land.

Total chance planning: early planning over an entire development area for the best overall realization of all objectives identified by broader planning.

Total resource plan: a plan for long-term forest management over an entire area, such as a watershed. The plan identifies known resource values, capabilities and sensitivities; confirms or refines management objectives for those values; and establishes detailed management guidelines by which to achieve those objectives on the ground.

Trade-off: a management decision whereby there is a reduction of one forest use in favour of another, such as a reduced timber yield in favour of improved wildlife habitat. In some cases, a management decision favouring one use in one location, is offset by a reverse decision favouring another use in another location.

Treatment prescription: operational details required for carrying out individual silviculture activities such as site preparation and planting.

Treatment season: the season or year the planned treatment activity will be carried out.

Treatment unit: the geographic unit of productive forest land area designated in a prescription for a specific silviculture activity or series of treatments.

Tree Farm Licence (TFL): TFLs are privately managed Sustained Yield Units. TFLs are designed to enable owners of Crown-granted forest lands and old temporary tenures or the timber licences which replace them, to combine these with enough unencumbered Crown land to form self-contained sustained yield management units. These licences commit the licensee to manage the entire area under the general supervision of the Forest Service. Cutting from all lands requires Forest Service approval through the issuance of cutting permits. TFLs should not be confused with Certified Tree Farms under the Taxation Act, though some Certified Tree Farm land (Crown-granted) may comprise a part of the TFL. A TFL has a term of 25 years.

Tree-length harvesting system: a method of harvesting that includes felling a tree, cutting of the top and delimbing it before transport to a mill.

TSA plan: the overall forest management plan developed for a TSA. The TSA Plan establishes the overall direction for the management of the timber, range and recreation resources under Forest Service jurisdiction in the TSA.

Turnout: a widening in the roadway where a vehicle may pull or park to allow other vehicles to pass safely.

	are restricted in their distribution over a natural landscape (e.g., freshwater wetlands within certain biogeoclimatic) or are restricted to a specific geographic area or a particular type of local environment; or
	were previously widespread or common but now occur over a much smaller area due to extensive disturbance or complete destruction by such practices as intensive harvesting or grazing by introduced species, hydro projects, dyking, and agricultural conversion.
	Threatened or endangered species: threatened or endangered species as identified by the Ministry of Environment, Lands and Parks. The taxa on the red list are either Extirpated, Endangered or Threatened, or are being considered for such status. Any indigenous taxon (species or sub-species) threatened with imminent extinction or extirpation throughout all or a significant portion of its range in British Columbia is Endangered. Threatened taxa are those indigenous species or sub-species that are likely to become endangered in British Columbia if factors are nor reversed.
	Timber: trees, whether standing, fallen, living, dead, limbed, bucked or peeled.
	Timber cruising: the collection of field data on forests commonly by the measurement and recording of information in sample plots. Includes the measurement and estimation of volumes of standing trees.
	Timber harvesting land base: the portion of the total area of a management unit considered to contribute to, and be available for, long-term timber supply. The harvesting land base is defined by reducing the total land base according to specified management assumptions.
	Timber licence: area-based tenures which revert to the government when merchantable timber on the area has been harvested and the land reforested. Many of these licences have been incorporated into tree farm licences.
	Timber management prescriptions: recommended forest management practices, usually pertaining to the sub-unit and operational levels of planning.
	Timber mark: a hammer indentation made on cut timber for identification purposes.
	Timber operability (see also Operable timber): in a planning context, the term refers to the economic suitability of timber for harvesting. Parameters to consider in assessing operability include: terrain, timber quality, timber size, operating season, labour costs, development costs, and transportation costs. In the Environmental Protection Area program, operability refers to freedom from harvesting constraints which include environmental protection and other forest uses.
	Timber sale licence: an agreement entered into under Part 3, Division (3) of the Forest Act. A timber sale licence usually defines a specific volume of timber to be harvested from a specific area. In special circumstances, an allowable annual cut (AAC) is specified. Allows the orderly harvest of relatively small volumes of timber by
	operators with small cuts;
	operators registered under the Small Business Forest Enterprise Program or others with temporary cutting rights; and
	holders of pulpwood agreements.
	Timber supply: the available timber categorized by species, end-use, and relative value.
	Timber supply analysis: an assessment of future timber supplies over long planning horizons (more than 200 years) by using timber supply models for different scenarios identified in the planning process.
	Timber Supply Area (TSA): An integrated resource management unit established in accordance with Section 6 of the Forest Act. TSAs were originally defined by an established pattern of wood flow from management units to the primary timber-using industries.
	Timber Supply Block (TSB): a division of a timber supply area.
	Timber supply model: an analytical model (usually computer-based) that simulates the harvest and growth of collections of forest stands over several decades according to specific data and management assumptions.
	Timber utilization: the dimensions and quality of timber that is actually cut and removed from an area.
	Tolerance: the ability of an organism or biological process to subsist under a given set of environmental conditions. The range of these under which it can subsist, representing its limits of tolerance, is termed its ecological amplitude. For trees, the tolerance of most practical importance is their ability to grow satisfactorily in the shade of and in competition with other trees.
	Top height: the average height of the hundred trees of largest diameter per hectare.
	Topographic break: a distinct change in the slope of the land.
	Topography: the physical features of a geographic area, such as those represented on a map, taken collectively; especially, the relief and contours of the land.
	Total chance planning: early planning over an entire development area for the best overall realization of all objectives identified by broader planning.
	Total resource plan: a plan for long-term forest management over an entire area, such as a watershed. The plan identifies known resource values, capabilities and sensitivities; confirms or refines management objectives for those values; and establishes detailed management guidelines by which to achieve those objectives on the ground.
	Trade-off: a management decision whereby there is a reduction of one forest use in favour of another, such as a reduced timber yield in favour of improved wildlife habitat. In some cases, a management decision favouring one use in one location, is offset by a reverse decision favouring another use in another location.
	Treatment prescription: operational details required for carrying out individual silviculture activities such as site preparation and planting.
	Treatment season: the season or year the planned treatment activity will be carried out.
	Treatment unit: the geographic unit of productive forest land area designated in a prescription for a specific silviculture activity or series of treatments.
	Tree Farm Licence (TFL): TFLs are privately managed Sustained Yield Units. TFLs are designed to enable owners of Crown-granted forest lands and old temporary tenures or the timber licences which replace them, to combine these with enough unencumbered Crown land to form self-contained sustained yield management units. These licences commit the licensee to manage the entire area under the general supervision of the Forest Service. Cutting from all lands requires Forest Service approval through the issuance of cutting permits. TFLs should not be confused with Certified Tree Farms under the Taxation Act, though some Certified Tree Farm land (Crown-granted) may comprise a part of the TFL. A TFL has a term of 25 years.
	Tree-length harvesting system: a method of harvesting that includes felling a tree, cutting of the top and delimbing it before transport to a mill.
	TSA plan: the overall forest management plan developed for a TSA. The TSA Plan establishes the overall direction for the management of the timber, range and recreation resources under Forest Service jurisdiction in the TSA.
	Turnout: a widening in the roadway where a vehicle may pull or park to allow other vehicles to pass safely.