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U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Reforestation Glossary

Appropriate Forest Cover - Vegetation composed of plant communities, which would occur naturally on similar sites depending upon the stage of plant succession. Forbs, grasses, and shrubs in their proper ratios are also elements of forest cover.

Current Maintenance Reforestation - All acres in need of reforestation that have been deforested by any natural or human cause, such as, fire, wind, insects, disease, or timber harvest since July 1, 1975. The NFMA requirement that all backlog reforestation be completed by September 30, 1985, was accomplished, therefore, all reforestation is now considered current work.

Advance Regeneration (also called advance reproduction or advance growth) - Seedlings or saplings that develop or are present in the understory.

Age Class (cohort) - One of the intervals into which the age range of trees is divided for classification or use. A distinct aggregation of trees originating from a single natural event or regeneration activity, or a grouping of trees, such as a 10-year age class, as used in inventory or management.    

Artificial Regeneration (Reproduction) - A group or stand of young trees created by direct seeding or by planting seedlings or cuttings.

Cleaning

  1. An intermediate, release treatment made in an age class not past the sapling stage to free the favored trees from less desirable individuals of the same age class that overtop them or are likely to do so (see improvement cutting, liberation, and weeding).
  2. A release treatment designed to eradicate individual trees infected with diseases, such as dwarf mistletoe.

Clearcut

  1. A stand in which essentially all trees have been removed in one operation to produce an even-aged stand. Depending on management objectives, a clearcut may or may not have reserve trees left to attain goals other than regeneration (see regeneration method (two-aged methods).
  2. A regeneration or harvest method that removes essentially all trees in a stand.

Clearcutting Regeneration Method - The cutting of essentially all trees, producing a fully exposed microclimate for the development of a new age class. Regeneration can be from natural seeding, direct seeding, planted seedlings, coppice, or advance reproduction. Cutting may be done in groups or patches (group or patch clearcutting), or in strips (strip clearcutting). The management unit or stand in which regeneration, growth, and yield are regulated consists of the individual clearcut stand. When the primary source or regeneration is advance reproduction, the preferred term is overstory removal.


Clearcutting Regeneration Method with Reserves - A clearcutting regeneration method in which varying numbers of reserve trees are retained to achieve goals other than regeneration. This method produces a two-aged stand in which varying numbers of reserve trees are not harvested. If a minor, live component is left for snag replacement, the method is considered a clearcut method rather than clearcut with reserves.

Coppice Regeneration Method - An even-aged method of regenerating a stand in which the trees in the previous stand are cut and the majority of regeneration is from sprouts or root suckers.

Coppice Regeneration Method with Reserves - A coppice regeneration method in which varying numbers of reserve trees are retained to achieve goals other than regeneration. This method normally creates a two-aged stand. If a minor, live component is left for snag replacement, the method creates an even aged stand.

Even-aged Methods - Regeneration and maintenance of a stand with a single age class.

Even-aged Stand - A stand of trees composed of a predominately single age class in which the range of tree ages is usually les than 20 percent of the intended rotation (see clearcutting, seed-tree, shelterwood, and coppice regeneration).

Even-aged Silvicultural System - A planned sequence of treatments designed to maintain and regenerate a stand with predominately one age class. The range of tree ages is usually less than 20 percent of the rotation (see clearcutting, seed-tree, shelterwood, and coppice regeneration methods).

Forest - An ecosystem characterized by more or less dense and extensive tree cover, often consisting of stands varying in characteristics such as species composition, structure, age class, and associated processes, and commonly including meadows, streams, fish and wildlife.

Forest Regulation - The technical (in contrast to the administrative and business) aspects of controlling stocking, harvest, growth, and yields to meet management objectives including sustained yield.

Group Selection Regeneration Method - A method of regenerating uneven-aged stands in which trees are cut, in small groups, and new age classes are established. The width of groups is commonly approximately twice the height of the mature trees, with small openings providing microenvironments suitable for tolerant regeneration, and the larger openings providing conditions suitable for regeneration that is more intolerant. In the group selection regeneration method, the management unit or stand in which regeneration growth and yield are regulated consists of a landscape containing an aggregation of groups.

Harvest Activity - A reference to a specific type of cut applied under a regeneration method or intermediate treatment. Refer to the TRACS-SILVA Table S1020 for valid codes. (TRACS-SILVA Data Dictionary).

Improvement Cutting - An intermediate treatment made in a stand, pole-sized or larger, primarily to improve composition and quality by removing less desirable trees of any species.

Intermediate Treatment - A collective term for any treatment or tending designed to enhance growth, quality, vigor, and composition of the stand after establishment or regeneration and prior to final harvest.           

Liberation Cut - A intermediate, release treatment made in a stand not past the sapling stage in order to free the favored trees from competition of older, overtopping trees.

Overstory Removal - The cutting of trees comprising an upper canopy layer in order to release advance regeneration in an understory. Overstory removal is only applicable to the clearcutting regeneration method and only when the primary source of regeneration is advance reproduction.

Patch (Group) Clearcutting - Under an even-aged method, a modification of the clearcutting method where patches (groups) are clearcut in an individual stand boundary in two or more entries. Under a two-aged method, varying numbers of reserve trees are not harvested in the patches (groups), to attain goals other than regeneration.

Preparatory Cut - An optional type of cut that enhances conditions for seed production and establishment applied under the shelterwood regeneration methods.

Regeneration Method - A cutting procedure by which a new age class is created. The major methods are clearcutting, seed-tree, shelterwood, selection, and coppice. Regeneration methods are grouped into four categories: coppice, even-aged, two-aged, and uneven-aged.

Reforestation Treatment - A reference to a specific reforestation activity used to establish reproduction in a stand. Treatments include planting, direct seeding, coppice or root suckers, site preparation for natural reproduction (regeneration), or natural regeneration without site preparation. These treatments typically start at the beginning phases of a regeneration method just subsequent to the harvest, such as: clearcutting, clearcutting with reserves, overstory removal, seed-tree, seed-tree with reserves, shelterwood, shelterwood with reserves, coppice, coppice with reserves, single-tree selection, and group selection.

Release - An intermediate treatment designed to free young trees from undesirable, usually overtopping, competing vegetation.

Reserve Trees - Live trees, pole-sized or larger, retained in either a dispersed or aggregated manner after the regeneration period under the clearcutting with reserves, seed-tree with reserves, shelterwood with reserves, group selection with reserves, or coppice with reserves regeneration methods. Trees are retained for resource purposes other than regeneration.

Salvage Cutting - The removal of dead trees or trees being damaged or dying due to injurious agents other than competition, to recover value that would otherwise be lost.

Sanitation Cutting - The removal of trees to improve stand health by stopping or reducing actual or anticipated spread of insects and disease.

Seed Cut - A type of cut that removes trees except those needed for regeneration and reserve trees. Prepares the seed bed and creates a new age class in an even-aged or two-aged stand under the seed-tree or shelterwood regeneration method. If reserve trees are retained, it is under a two-aged method of seed tree or shelterwood regeneration methods.

Seed-Tree Regeneration Method - An even-aged regeneration method in which a new age class develops from seeds that germinate in fully-exposed micro-environments after removal of the previous stand, except for a small number of trees left to provide seed. All trees are cut except for a small number of widely dispersed trees retained for seed production and to produce a new age class in fully exposed microenvironment. Seed trees are usually removed after regeneration is established unless some are retained to meet other resource objectives (snags replacement). Under a two-aged method (seed tree with reserves), some, or all of the seed trees are retained after regeneration has become established to attain goals other than regeneration. When the Seed Tree method is employed, the sequence of activities can include 1) seed cut (establishment cut) to establish a new age class and, 2) Steed Tree removal cut.

Seed-Tree Removal Cut - A final removal cut that releases established regeneration from competition with seed trees after they are no longer needed for seed under the seed-tree regeneration method. Reserve trees are retained during the removal cut if it is a sequence of the seed-tree with reserves regeneration method.

Seed Tree Regeneration Method with Reserves - A seed-tree regeneration method in which some or all of the seed trees are retained after regeneration has become established to attain goals other than regeneration. This method creates an even-aged stand or a two-aged stand depending on management goals. Reserve trees may also include those trees that are not expected to provide seed for desirable regeneration.

Seed Tree Removal Cut with Reserves - Under the two-aged method, seed tree regeneration method, the final removal of some of the remaining crop trees (seed trees) after regeneration is established. Some seed trees are retained to attain goals other than regeneration.

Shelterwood Regeneration Method - A method of regenerating an even-aged stand in which a new age class develops beneath the moderated microenvironment provided by the residual trees. When the shelterwood regeneration method is employed, the sequence of treatments can include three distinct types of cuttings:

  1. an optional preparatory cut to enhance conditions for seed production;
  2. a shelterwood seed cut (establishment cut) to establish a moderated micro-environment, prepare the seed bed, and create a new age class; and
  3. a shelterwood removal cut to release established regeneration from competition with the overwood.

Cutting may be done uniformly throughout the stand (uniform shelterwood), in groups or patches (group shelterwood), or in strips (strip shelterwood).

Shelterwood Removal Cut - A final removal cut that releases established regeneration from competition with shelter trees after they are no longer needed for shelter under the shelterwood regeneration method.

Shelterwood with Reserves Regeneration Method - A regeneration method in which some or all of the shelter trees are retained to attain goals other than regeneration. This method creates an even-aged stand or a two-aged stand if sufficient trees are reserved.

Shelterwood Removal Cut with Reserves - A final removal cut that releases established regeneration from competition with shelter trees after they are no longer needed for shelter under the shelterwood with reserves regeneration method. Reserve trees are retained during the final removal cut if it is a sequence of the shelterwood with reserves regeneration method (consistent with ST sequence).

Silviculture - The art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society on a sustainable basis.

Silvicultural Prescription - A document written or approved by a certified silviculturist that describes management activities needed to implement silvicultural treatment or treatment sequence. The prescription documents the results of an analysis of present and anticipated site conditions and management direction. It also describes the desired future vegetation conditions in measurable terms (FSM 2478.03). It documents a planned series of treatments designed to change current stand structure and composition to one that meets management goals. The prescription normally considers ecological, economic, and societal objectives and constraints.

Single Tree Selection Regeneration Method - An uneven-aged method where individual trees of all size classes are removed more or less uniformly throughout the stand, to promote growth of remaining trees and to provide space for regeneration.

Stand - A contiguous group of trees sufficiently uniform in age class distribution, composition, and structure, and growing on a site of sufficiently uniform quality, to be a distinguishable unit, such as mixed, pure, even-aged, and uneven-aged stands. A stand is the fundamental unit of silviculture reporting and record-keeping. Stand may be analogous to Activity Unit.

Stand Composition - The proportion of each tree species in a stand expressed as a percentage of the total number, basal area, or volume of all tree species in the stand.

Stand Clearcutting - A type of clearcutting where removal of essentially all trees in the previous stand, producing a fully exposed microclimate for the development of a new age class. Under a two-aged method, varying numbers of reserve trees are not harvested to attain goals other than regeneration.

Strip Clearcutting - A type of clearcutting involving strip cutting in two or more entries, separated by a few years, resulting in an even-aged or two-aged stand under the clearcutting regeneration method. Reserve trees may or may not be retained. Under an even-aged method, a modification of the clearcutting method where alternate or progressive strips are clearcut in an individual stand boundary in two or more entries. Under a two-aged method, varying numbers of reserve trees are not harvested in the strips, to attain goals other than regeneration.

Thinning - An intermediate treatment made to reduce stand density of trees primarily to improve growth, enhance forest health, or to recover potential mortality. Includes crown thinning (thinning from above, high thinning), free thinning, low thinning (thinning from below), mechanical thinning (geometric thinning), and selection thinning (dominant thinning).

Two-Aged Method - Regeneration and maintenance of stands with two age classes. The resulting stand may be two-aged or tend towards and uneven-aged condition as a consequence of both an extended period of regeneration establishment and the retention of reserve trees (green trees) that may represent one or more age classes.

Two-Aged Stand - A growing area with trees of two distinct age classes separated in age by more than plus or minus 20 percent of rotation.

Two-Aged Silvicultural System - A planned sequence of treatments designed to regenerate or maintain a stand with two age classes.

Uneven-aged Methods - Regeneration and maintenance of stands with a multiaged structure by removing some trees in all size classes either singly or in groups or in strips.

Uneven-aged Stand - A stand of trees of three or more distinct age classes, either intimately mixed or in groups.

Uneven-aged Silvicultural System - A planned sequence of treatments designed to regenerate or maintain a stand with three or more age classes Includes single-tree selection, and group selection regeneration methods.

Weeding - A release treatment in stands not past the sapling stage that eliminates or suppresses undesirable vegetation regardless of crown position.