Glossary of Forestry Terms - S part 2

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S - part 2
Soil pit an excavation into the mineral soil of sufficient depth to allow assessment of variability in soil physical properties within a defined area of land.
Soil productivity the capacity of a soil, in its normal environment, to support plant growth.
Soil verification pit an excavation into the mineral soil of sufficient depth to allow assessment of the soil properties used to evaluate soil productivity and sensitivity to forest management-related disturbances. This generally requires an excavation 90 cm deep unless a watertable, compact soil, or bedrock is encountered closer to the soil surface, in which case the depth to one of these layers is the minimum depth of pit required.
Spacing the removal of undesirable trees within a young stand to control stocking, to maintain or improve growth, to increase wood quality and value, or to achieve other resource management objectives.
Special forest products these are: poles; posts; pilings; shakes; shingle bolts; Christmas trees; building logs; mining timbers, props, and caps; cribbing; firewood and fuel logs; hop poles; orchard props; car stakes; round stakes, sticks, and pickets; split stakes, pickets, palings, and lagging; and shake bolts, blocks, and blanks.
Special sale area See Regulated unit.
Species a singular or plural term for a population or series of populations of organisms that are capable of interbreeding freely with each other but not with members of other species. Includes a number of cases:
  • endemic species: a species originating in, or belonging to, a particular region. Both "endemic" and "indigenous" are preferred over "native."
  • exotic species: a species introduced accidentally or intentionally to a region beyond its natural range. "Exotic" is preferred over "alien," "foreign" and "non-native.'
  • subspecies: a subdivision of a species. A population or series of populations occupying a discrete range and differing genetically from other subspecies of the same species.
Species at risk
  • any wildlife species that is threatened, endangered, sensitive or vulnerable, and
  • any threatened and endangered plants or plant communities that require protection.
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Species composition the percentage of each recognized tree species comprising the forest type based upon the gross volume, the relative number of stems per hectare or basal area.
Species conversion a change from one tree species to another.
Spot burning a modified form of broadcast burning in which only the larger accumulations of slash are fired and the fire is confined to these spots.
Spring a flow of ground water emerging naturally onto the earth's surface and used as a domestic water source within a community watershed. The watershed area of a spring is defined as the total recharge area of the spring.
Stabilized road width the width of the travelled portion of the road that has been surfaced with material of sufficient strength and quantity to support the intended traffic.
Stagnant of stands whose growth and development have all but ceased due to poor site and/or excessive stocking.
Stand a community of trees sufficiently uniform in species composition, age, arrangement, and condition to be distinguishable as a group from the forest or other growth on the adjoining area, and thus forming a silviculture or management entity.
Stand composition the proportion of each tree species in a stand expressed as a percentage of either the total number, basal area or volume of all tree species in the stand.
Stand conversion changing the species composition of a stand to more desirable tree species which are less susceptible to damage or mortality from certain insects or diseases.
Stand density a relative measure of the amount of stocking on a forest area. Often described in terms of stems per hectare.
Stand development the part of stand dynamics concerned with changes in stand structure over time.
Stand dynamics the study of changes in forest stand structure over time, including stand behavior during and after disturbances.
Stand level the level of forest management at which a relatively homogeneous land unit can be managed under a single prescription, or set of treatments, to meet well-defined objectives.
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Stand management prescription a site-specific plan describing the nature and extent of the silviculture activities that will occur on a free-growing stand to facilitate the achievement of, among others, social, economic, and environmental objectives.
Stand model a computer model that forecasts the development of a forest stand, usually in terms of stand attributes such as mean diameter or height.
Stand strategy a documented plan of stand treatments to achieve management objectives during the life of a particular stand.
Stand structure (stand types) the distribution of trees in a stand, which can be described by species, vertical or horizontal spatial patterns, size of trees or tree parts, age, or a combination of these.
Stand table a summary table showing the number of trees per unit area by species and diameter class, for a stand or type. The data may also be presented in the form of a frequency distribution of diameter classes.
Stand tending a variety of forest management treatments, including spacing, fertilization, pruning, and commercial thinning, carried out at different stages during a stand's development.
Standard the required level or measure of practice established by legislation.
Standing status held by a person or group which allows the person or group to challenge or appeal a particular decision.
Statutory framework where forest practices are primarily regulated by legislation.
Stewardship caring for land and associated resources and passing healthy ecosystems to future generations.
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Stocking a measure of the area occupied by trees, usually measured in terms of well-spaced trees per hectare, or basal area per hectare, relative to an optimum or desired level.
Stocking class a numeric code representing a range of stems per hectare, sometimes estimated by crown closure on aerial photographs, e.g. stocking class 1 is mature with 76+ stems/ha of > 27.5 cm DBH; class 2 is mature with < 76 stems/ha; class 0 is immature.
Stocking plan a plan that provides objectives and strategies for land allocation and/or resource management, including regional plans, subregional plans, and local resource plans.
Stocking standard he required range of healthy, well-spaced, acceptable trees.
Stocking survey the determination of the stocking of an area of both well-spaced and total trees; also used to generate an inventory label.
Strategic plan a plan that provides objectives and strategies for land allocation and/or resource management, including regional plans, subregional plans, and local resource plans.
Strategy a broad non-specific statement of an approach to accomplishing desired goals and objectives.
Stream a watercourse, having an alluvial sediment bed, formed when water flows on a perennial or intermittent basis between continuous definable banks.
Stream bank the rising ground bordering a stream channel.
Stream channel the streambed and banks formed by fluvial processes, including deposited organic debris.
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Stream class
  • Stream Class A - includes streams or portions of streams that are frequented by anadromous salmonids and/or resident sport fish or regionally significant fish species; or streams identified for fishery enhancement in an approved fishery management plan; stream gradient is usually less than 12 percent.
  • Stream Class B - includes streams or portions of streams populated by resident fish not currently designated as sport fish or regionally significant fish; stream gradient is usually 8-20 percent.
  • Stream Class C - includes streams or portions of streams not frequented by fish; stream gradient is usually greater than 20 percent.
Stream culvert a culvert used to carry stream flow in an ephemeral or perennial stream channel from one side of the road to the other.
Stream gradient the general slope, or rate of vertical drop per unit of length of a flowing stream.
Streambed the bottom of the stream below the usual water surface.
Streamside Management Zone (SMZ) the land, together with the vegetation that supports it, immediately in contact with the stream and sufficiently close to have a major influence on the total ecological character and functional processes of the stream.
See also Riparian Management Area.
Stumpage is the fee that individuals and firms are required to pay to the government when they harvest Crown timbe. Stumpage is determined through a complex appraisal of each stand or area of trees that will be harvested for a given timber mark. A stumpage rate ($ per m3) is determined and applied to the volume of timber that is cut (m3).
Subgrade the material movement necessary to construct the roadway, excluding surfacing.
Substructure the part of a bridge that supports the superstructure and carries all the applied lateral and vertical loads; includes caps, sills, piles, and posts, each comprising elements known as abutments and piers.
Subsurface drainage water flow through permeable soil or rock beneath the surface of the land.
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Sub-unit plan the fourth level of planning in a ministry hierarchical planning system. The aggregation of a number of courses of action in map and written form designed to achieve sub-unit objectives. Normally centred on watersheds.
Succession the gradual supplanting of one community of plants by another, the sequence of communities being termed a sere and each stage seral.
Suitability mapping a habitat interpretation that describes the current potential of a habitat to support a species. Habitat potential is reflected by the present habitat condition or successional stage.
Superstructure the part of a bridge found above or supported by the caps or sills, including the deck, girders, stringers, and curbs.
Supply block an area of Crown land that is relatively homogeneous with respect to forest characteristics, access development and management concerns. Supply blocks are the next smaller timber management unit within a Timber Supply Area.
Surface soil erosion means for an area where a forest practice has been carried out, the movement of soil particles from the area by wind, gravity or water at a rate that is greater than that which would have occurred had the forest practice not been carried out.
Surplus forest a forest in which existing stands can provide more harvest volume than is needed to maintain the harvest at the level of long run sustained yield until the stands created when the existing stands are cut become available for harvest.
See also Deficit forest.
Sustainability the concept of producing a biological resource under management practices that ensure replacement of the part harvested, by regrowth or reproduction, before another harvest occurs.
Sustainable development preservation and protection of diverse ecosystems-the soil, water, plants, animals, insects and fungi while maintaining the forest's productivity.
Sustainable forest management management regimes applied to forest land which maintain the productive and renewal capacities as well as the genetic, species and ecological diversity of forest ecosystems.
Sustained yield a method of forest management that calls for an approximate balance between net growth and amount harvested.
Switchback a horizontal road curve used for surmounting the grade of a step hill, usually with a small radius (15-10 m) and curving 180 degrees.
System road a permanent road required for long-term management of the forest.
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