Forestry Glossary : S

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Salvage Cut

The harvesting of trees that have been or are soon to be damaged beyond recovery (by insects, disease, or the environment) in order to utilize the timber before further decline occurs.

Sanitation Cut

The harvesting or destruction of trees infected or highly susceptible to insects or disease in order to prevent the spread to the forest stand.

Sanitation Measures

The removal of dead, damaged, or susceptible trees or their parts, or of vegetation that serves as alternative host for crop-tree pathogens, to prevent or control the spread of pests or pathogens.

Sap

The liquid that rises from the roots of a tree. Sap consists of water and minerals. In the spring it also contains sugars that stimulate growth.

Sapling

A small tree, usually defined as being between 5 cm and 10 cm dbh.

Sapwood

The outer layers of wood in a tree; contains living cells and reserve materials and is responsible for nutrient transportation.

Saskatchewan Forest Habitat Project

A partnership established in 1989 involving Wildlife Habitat Canada, Saskatchewan Wildlife Federation, The Federation of Saskatchewan Indian Nations, Weyerhaeuser Canada Saskatchewan Division, Saskatchewan Environment and Resource Management, Forestry Canada through the CanadaSaskatchewan Partnership Agreement in Forestry and Prince Albert National Park to cooperatively balance timber production and wildlife habitat objectives.

Satellite Nursery

see Field Nursery

Satisfactorily Stocked

see Stocking: satisfactorily stocked

Sawlog

A log designated to produce a sawn product Ñ usually at least 30 cm in diameter.

Sawtimber

Trees that will yield logs suitable in size and quality for the production of lumber.

Scarification

Loosening the topsoil of open areas or breaking up the forest floor in preparation for regenerating by direct seeding or natural seedfall; a seedbed preparation treatment intended to assist the germination of natural seed from either standing trees or slash or to promote the occurrence of coppice or sucker growth. The operation of breaking up the forest floor and top soil in preparation for natural or artificial regeneration.

Second Growth

The forest growth that has developed (naturally or artificially) following the removal of the original virgin forest.

Seed Bed

1. In natural regeneration, the soil or forest floor on which seed falls.

2. In nursery practice, a prepared area over which seed is sown.

Seed Collection Area

A forest stand that exhibits good characteristics of growth, form, and vigour and that is not managed for cone production, but from which seed is collected, usually at time of harvest.

Seed Cutting

Removing trees in a mature stand so as to effect permanent opening of its canopy (if there was no preparatory cutting to do this) and so provide conditions for securing regeneration from the seed of trees retained for that purpose; the first of the shelterwood cuttings under a shelterwood system.

Seed Orchard

A plantation of trees, assumed or proven genetically to be superior, that has been isolated so as to reduce pollination from genetically inferior outside sources, and intensively managed to improve the genotype and produce frequent, abundant, and easily harvestable seed crops. A clonal seed orchard is established by setting out clones as grafts or cuttings; a seedling seed orchard is established from selected seedling progenies.

Seed Production Area

A forest stand identified as a good source of seed and in which individual trees are evaluated for desired characteristics. Unwanted trees and competing trees are removed to promote cone production. Seed is collected during the life of the stand.

Seed Source

The locality where a seed lot was collected. If the stand from which collections were made was exotic, the place where its seed originated is the original seed source.

Seed Spot

A prepared, limited space, e.g., a small, cultivated patch, within which (tree) seeds are sown.

Seed Trap

A device for catching the seeds falling on a small area of ground, from trees or shrubs. Used for determining the amount of seedfall and the time, period, rate, and distance of dissemination.

Seed Tree

A tree selected, and often reserved, for seed collection or provision of seed for natural regeneration.

Seed-Tree Harvest Cut

A harvest cut on which all of the trees are removed from the harvest area at one time, except for a few scattered trees that are left to provide seed to establish a new forest stand.

Seed-Tree Method

A method of regenerating a forest stand in which all trees are removed from the area except for a small number of seed-bearing trees that are left singly or in small groups. The objective is to create an even-aged stand.

Seed Year

The year in which a tree species produces, either as an individual or a crop, an adequate amount of seed; applies to any species but particularly to those with irregular or infrequent seed production. Many periodic seeders produce heavy (bumper) seed crops during their seed years.

Seeding

aerial: Broadcast seeding of seeds or seed pellets from aircraft.
broadcast: The sowing of seeds more or less evenly over a whole area on which a forest stand is to be raised.
direct seedling: The artificial systematic sowing of seeds by manual or mechanical means in an area on which a forest stand is to be raised.
drill: The sowing of seeds in shallow furrows across a whole area on which a forest stand is to be raised.
natural seedling: The dispersal by natural agents of seeds from standing trees in proximity to a regenerating area or from slash scattered over that area. Seeds may be dispersed by wind, birds, mammals, gravity, or flowing water.
spot: The sowing of seeds within small, cultivated, or otherwise-prepared patches, many of which are distributed over a whole area on which a forest stand is to be raised.

Seedling

A young tree, grown from seed, from the time of germination to the sapling stage, having a diameter at breast height equal to or less than 1 cm. A tree, usually defined as less than 5 cm in dbh, which has grown from a seed (in contrast to a sprout).

bare-root: A seedling to be planted with its roots bare of soil.
container: A seedling grown in a container and that is to be planted with roots still in its growth medium.
plug: A seedling lifted from its container with roots and rooting medium left undisturbed.

Selection

Choosing individuals with desired qualities to serve as parents for the next generation.

Selection Cutting

Annual or periodic cutting of trees chosen individually or by groups, in an uneven-aged stand, in order to recover the yield and develop a balanced uneven-aged stand structure, while providing the cultural measures required for tree growth and seedling establishment. The cuts are usually a mix of regeneration cuts and improvement cuts. (Selection cutting is not the same as selective cutting.)

Selection Differential

The average phenotypic value of the selected individuals, expressed as a deviation from the population mean.

Selection Method

A method of regenerating a forest stand and maintaining an uneven-aged structure by removing some trees in all size classes either singly or in small groups or strips.

Selection System

The removal of mature trees, either as scattered individuals or in small groups, at relatively short intervals and repeated indefinitely. The objective is representation of all ages of trees throughout the stand to maximize growth of a quality product on a continuous basis.

Selection Thinning

see Thinning: selection

Selective Cutting

see High Grading

Selective Logging

see High Grading

Seral

see Succession

Serotinous

Coming late; particularly applied to plant species or individuals that flower or fruit late in the season and to fruit or cones that remain on the tree without opening for one or more years (e.g., Pinus contorta and Pinus banksiana), but also to bud opening and leaf shedding.

Shade-Tolerant

The capacity of a tree to survive and grow in the shade of, and in competition with, other trees.

Shearing

1. A method of harvest using mechanical shears.

2. The shaping of a tree crown, particularly with respect to Christmas trees or ornamental by clipping and pruning.

3. A method of site preparation in which all standing material is removed at ground line using a shear blade attached to a large tractor. Known in Manitoba as shear blading.

Shelterwood Cutting

Any regeneration cutting in a more or less regular and mature crop, designed to establish a new crop under the protection (overhead or side) of the old, as typically in shelterwood systems, or where the resultant crop will be more or less regular.

irregular shelterwood system: Harvest cutting in which opening of canopy is irregular and gradual; generally in groups, with the final cutting often in strips; regeneration natural; regeneration interval long, often up to half the rotation, and the resultant crop considerably uneven-aged and irregular. Much of the harvesting of Canadian old-growth conifer stands composed of tolerant species has been a type of irregular shelterwood.
strip shelterwood: A shelterwood system in which regeneration cuttings are carried out on fairly wide strips, generally against the prevailing wind, and progress rapidly; regeneration is mainly natural, regeneration interval short, and resultant crop fairly even-aged and regular.

Shrub

A low-growing perennial plant with a persistent woody stem and low branching habit.

Silt

A soil component consisting of particles between 0.05 and 0.002 mm in diameter.

Silvics

The study of the life cycle and characteristics of forest trees and stands with particular reference to local factors and environmental requirements.

Silvicultural Decision Model

A computer model or system that permits the simulation and possibly prediction of the interaction of such factors as site class, access, managed-stand volume, and logging costs to assist in decision making regarding silvicultural practices in individual stands.

Silvicultural Regime

A series of stand tending (thinning, pruning, etc.) treatments applied after regeneration to achieve a specific stand management objective.

Silvicultural System

A process, following accepted silvicultural principles, whereby forest crops are tended, harvested, and regenerated resulting in the production of crops of distinctive form.

Silviculture

The art, science, and practice of cultivating continuous forest crops based on a knowledge of species silvics.

Single-Tree Selection Method

A method of regenerating uneven-aged stands in which individual trees are removed more or less uniformly throughout the stand.

Site

a) A grouping of trees occupying a given area and sufficiently uniform in composition, age, and condition so as to be distinguisable from the forest on adjoining areas. A forest stand is said to be pure if 80 per cent or more of the trees present are of the same species. If less than 80 per cent of all trees present are of the same species, the stand is said to be mixed.

b) The soil, moisture, and environmental conditions of an area, particularly as this determines the type and quality of the vegetation the area can carry.

Site Capability

The mean annual increment in merchantable volume which can be expected for a forest area, assuming it is fully stocked by one or more species best adapted to the site, at or near rotation age. Expressed in cubic metres per hectare.

Site Class

Any interval into which the site index range is divided for purposes of classification and use.

Site Index

An expression of forest site quality based on the height of the dominant trees at a specified age (usually 50 years).

Site Preparation

Disturbance of the forest floor and topsoil to create suitable conditions for natural or artificial regeneration by mechanical, chemical, or by prescribed burning methods.

Site Quality

The productive capacity of a site; usually expressed as volume production of a given species per unit area (cubic metres per hectare) or per unit of time (cubic metres per year).

Size Classes

Tree sizes representing stages in the development of a tree or stand.

Skidding

The removal of logs from a logging operation by dragging them along the ground attached by ropes or chains to a power source, such as horses or mechanical tractors.

Slash

Residue, including tree tops, branches, and bark, left on the ground after logging, pruning, or other forest operations.

Snags

(Current usage.) Either a standing tree that has begun to decay and has value as a wildlife habitat or a tree that has been felled but has been caught on the way down.

Softwoods

See conifer.

Spacing

noun: The distance between trees in a plantation, a thinned stand, or a natural stand.

verb: see Thinning: spacing

Springwood

A light ring of wood produced during the active growing period in the spring of the year. It consists of large thin-walled cells.

Sprout

A shoot that has grown from the base, stump, or root of another tree.

Stagnant

Of stands whose growth and development have all but ceased due to poor site and/or excessive stocking.

Stakeholder

Concerned individuals or groups.

Stand

A community of trees possessing sufficient uniformity in composition, age, arrangement, or condition to be distinguishable from the forest or other growth on adjoining areas, thus forming a silvicultural or management entity.

Stand Density

A quantitative measure of tree cover on an area in terms of biomass, crown closure, number of trees, basal area, volume, or weight. In this context, tree cover includes seedlings and saplings; hence, the concept carries no connotation of a particular age. Expressed on a per hectare basis.

Stand Density Index

Any index for evaluating stand density such as those of Curtis, Mulloy, Reinecke.

Stand Density Management Diagram

A two-dimensional graph showing the logarithmic relationship between declining mean stand frequency and increasing mean tree size as mean stand diameter and dominant height increase in pure even-aged stands.

Stand Model

A computer model that forecasts the development of a forest stand, usually in terms of mean stand attributes, e.g., mean diameter, height.

Stand Table

A summary table showing the number of trees per unit area by species and diameter classes, for a stand or type. The data may also be presented in the form of a frequency distribution of diameter classes.

Standard

A tree selected to remain standing, after the rest of the stand has been felled over a younger or a new crop, for some special purpose, e.g., shelter, seeding, production of a special quality or size of timber.

Stock Table

A summary table showing the volume of trees per unit area by species and diameter classes, for a stand or type.

Stocking

An expression of the adequacy of tree cover on an area in terms of crown cover, per cent stocking. number of trees, basal area or volume in relation to a pre-established norm (optimum for growths).

fully stocked: Productive forest land stocked with trees of merchantable species. These trees by number and distribution or by average dbh, basal area, or volume are such that at rotation age they will produce a timber stand that occupies the potentially productive ground. They will provide a merchantable timber yield according to the potential of the land. The stocking, number of trees, and distribution required to achieve this will be determined from regional or local yield tables or by some other appropriate method.
nonstocked: Productive forest land that lacks trees completely or that is so deficient in trees, either young or old, that at the end of one rotation, the residual stand of merchantable tree species, if any, will be insufficient to allow utilization in an economic operation.
normally stocked: Productive forest land covered with trees of merchantable species of any age. These trees, by number and distribution, or by average dbh, basal area, or volume, are such that at rotation age they will produce a timber stand of the maximum merchantable timber yield. This yield must satisfy the site potential of the land as reported by the best available regional or local yield tables. For stands of less than rotation age, a range of stocking classes both above and below normal may be predicted to approach and produce a normal stocking at rotation age and may, therefore, be included. This is because greater or lesser mortality rates will occur in over- or understocked stands as compared with those in a normal stand.
NSR (not sufficiently or not satisfactorily restocked or regenerated): Inadequate stocking. Productive forest land that has been denuded and has failed partially or completely to regenerate naturally or to be artificially regenerated. The regeneration must contain a minimum number of well-established, healthy trees that are free-to-grow and sufficient to produce a merchantable timber stand at rotation age. In a number of provinces, forest lands that have been recently harvested and that are not yet classified as satisfactorily stocked are classified as NSR. This classification does not necessarily imply that re-treatment is required to correct a failure to regenerate.
overstocked: Productive forest land stocked with more trees of merchantable species than normal or full stocking would require. Growth is in some respect retarded and the full number of trees will not reach merchantable size by rotation age according to the regional or local yield or stock tables for the particular site and species.
partially stocked: Productive forest land stocked with trees of merchantable species insufficient to utilise the complete potential of the land for growth such that they will not occupy the whole site by rotation age without additional stocking. Explicit definition in stems per hectare, crown closure, relative basal area, etc. is locally or regionally defined and is site-specific.
satisfactorily stocked: Productive forest land that has been regenerated naturally or artificially to at least a minimum number of well-established, healthy trees of merchantable species that are free-to-grow and sufficient to produce a merchantable timber stand at rotation age.

Stool

1. Silviculture: A living stump capable of producing sprouts.

2. Propagation: A living stump maintained to produce cuttings, layers, etc.

Story

A horizontal stratum or layer in a plant community; in forests, appearing as one or more canopies. A forest having more than two storys is called multistoried. A forest having one story (the main story) is called single-storied. A forest having two storys (the overstory and the understory) is called two-storied.

Strip Cutting

Removal of the crop in strips in one or more operations, generally for encouraging regeneration or protecting fragile sites. Considered in Ontario to be a variation of clearcutting.

Strip Shelterwood

see Shelterwood Cutting

Structure

The distribution of trees in a stand or group by age, size, or crown classes (e.g., all-aged, even-aged, uneven-aged, regular, and irregular structures).

Stump Treatment

Application of herbicides to or near hardwood stumps to prevent sprouts and suckers.

Stumpage

The monetary value of timber as it stands uncut in the woodlot.

Succession

The replacement of one plant community by another until ecological stability is achieved. The gradual supplanting of one community of plants by another, the sequence of communities being termed a sere and each stage seral.

Sucker

Sprouts growing from the root system as opposed to coppice shoots from the stump or root collar.

Summerwood

The less porous, usually harder portion of an annual tree ring that forms in the latter part of the growing season.

Suppressed Trees

Trees experiencing slowed growth resulting from being shaded by other trees.

Sustainable Development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Sustained Yield

The management of a resource for continuous production with the aim of achieving an approximate balance between net growth and harvest.