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The following terms are specific to this site and definitions are drawn from: Helms, J. A. 1998. The Dictionary of Forestry. Society of American Foresters. 224pp and Smith, D.M. 1986 The Practice of Silviculture. 8th ed. John Wiley and Sons. New York . 527 pp.



Acre: a unit of area equaling 43,560 square feet or 10 square chains.

Apical dominance: the upward growth of terminal shoot meristem(s) at the expense of lateral shoots below whose development they inhibit

Autoecology: the ecology of an individual organism or taxonomic group




Basal area (BA): the cross-sectional area of a single stem, including the bark, measured at breast height (4.5 ft or 1.37 m above the ground)

Biodiversity: The variety and abundance of life forms, processes, functions, and structures of plants, animals, and other living organisms, including the relative complexity of species, communities, gene pools, and ecosystems at spatial scales that range from local through regional to global

Biological legacy: an organism, a reproductive portion of an organism, or a biological derived structure or pattern inherited from a previous ecosystem -note biological legacies often include large trees, snags, and down logs left after harvesting to provide refugia and to structurally enrich the new stand

Blowdown: tree or trees felt or broken down off by wind

Boardfoot: the amount of wood contained in an unfinished board 1 in thick, 12 in long , and 12 in wide, abbreviated bd ft

Bolt: a short piece of pulpwood; a short log




Canker: a disease of the bark and cambium that causes a usually well defined sunken or swollen necrotic lesion

Cambium: a layer of living, meristematic cells between the wood of a tree

Cavity trees: living specimens of poor quality which as a result of low vigor and or broken branches allow invasion of decay insects and fungi, leading to the formation of decay cavities used by wildlife

Chain: a unit of length, a surveyor's chain equals 66 feet or 1/80-mile

Cleaning: a 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

Clearcutting: the cutting of essentially all trees, producing a fully exposed microclimate for the development of a new age class

Codominant: a tree whose crown helps to form the general level of the main canopy in even-aged stands or in uneven-aged stands, the main canopy of the tree's immediate neighbors, receiving full light from above and partial light from the sides

Cohort: a group of trees developing after a single disturbance, commonly consisting of trees of similar age, although it can include a considerable range of tree ages of seedling or sprout origin and trees that predate the disturbance

Commercial thinning: any type of thinning producing merchantable material at least equal to the value of the direct costs of the harvesting

Community: an assemblage of plants and animals living together and occupying a given area

Composition: 1. The constituent elements of an entity (e.g. the species that constitute a plant community) 2. 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

Conk: the visible fruiting body of a wood-destroying fungus which projects to some degree beyond the substrate (i.e. tree stem)

Coppice: to cut the main stem (particularly of broadleaved species) at the base or to injure the roots to stimulate the production of new shoots for regeneration

Cord: a stack of fuelwood, pulpwood or other material that measures 4 x 4 x 8 ft, or 128ft3

Course woody debris (CWD): any piece(s) of dead woody material on the ground in forest stands or in streams

Cover: any vegetation that shelters wildlife from predators or climatic extremes

Crop tree: any tree selected to become a component of a future commercial harvest

Cubic foot: a unit of true volume that measures 1 x 1 x 1 feet

Cunit: a unit of volume, usually pulpwood, consisting of 100 cubic feet of solid wood (not including bark or air volume)




Diameter at breast height (DBH, dbh): the diameter of the stem of tree measured at breast height (4.5 feet) from the ground

Disturbance: any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment

Dominant: an individual or species of the upper layer of the canopy




Ecoregion: a contiguous geographic area having a relatively uniform macroclimate, possibly with several vegetation types, and used as an ecological basis for management or planning

Ecosystem: a spatially explicit, relatively homogenous unit of the earth that includes all the interacting organisms and components of the abiotic environment within its boundaries

Even-aged stand: a stand of trees composed of a single class in which the range of tree ages is usually +/- 20 percent of rotation




Flitch: 1. a large piece from the side of a log, which is sawn or hewn on two or more sides, waney, bevel-edged or square-edged, and intended for further conversion 2. a package of sheets of veneer laid together in the sequence of their cutting




Gap: the space occurring in forest stands due to individual or group tree mortality or blowdown

Germination: The beginning of growth of a mature, generally dormant seed, spore, or pollen grain

Girdle: to make more or less continuous incisions around a living stem, through at least both the bark and cambium, generally with the object of killing the tree

Group selection: trees are removed and new age classes are established in small groups

Growing stock: all the trees growing in a forest or in a specified part of it, usually commercial species, meeting specified standards of size, quality, and vigor, and generally expressed in terms of number or volume




Habitat: the place, natural or otherwise, (including climate, food, cover, and water) where an animal, plant, or population naturally or normally lives and develops

Harvesting schedule: a process for allocating cutting and other silvicultural treatments over a forest with emphasis on which treatments to apply and where and when to apply them




Intermediate crown class: a tree whose crown extends into the lower portion of the main canopy of even-aged stands or, in uneven-aged stands, into the lower portion of the canopy formed by the tree's immediate neighbors, but shorter in height than the codominants and receiving little direct light from above and none from the sides

Intermediate treatment: Any treatment or tending designed to enhance the growth, quality, vigor, and composition of the stand after establishment or regeneration and prior to final harvest




J-roots: a root that is bent into a J-shape because the seedling was improperly planted in a hole or slit that was too shallow or narrow




Live crown ratio (LCR): the ratio of crown length to total tree height




Mast: the fruit of trees considered as food for livestock and certain kinds of wildlife

Mature: pertaining to a tree or even-aged stand that is capable of sexual reproduction, has attained most of its potential height growth, or has reached merchantability standards

Mean annual increment (MAI): the total increment of tree or stand (standing crop plus thinnings) up to a given age divided by the age

Mechanical thinning: the thinning of trees in either even-aged or uneven-aged stands, involving removal of trees in rows, strips, or by using fixed spacing intervals

Meristem: an organized, undifferentiated plant tissue with rapidly dividing cells that differentiate to form new tissues or organs




Overstory: the portion of the trees, in a forest of more than one story, forming the upper or upper-most canopy layer, e.g., in a two-storied forest, seed-bearers over regeneration , or standards over coppice




Pitch: natural resins often exude from wounds and are obtained commercially by tapping or extraction with solvents

Poletimber: A tree of a size between a sapling and a sawtimber tree. Hardwood trees ranging in size from 5 to 11 inches dbh, and conifers ranging in size from 5 to 9 inches dbh.

Population: a group of similar individuals sharing a common gene pool, delimited in range by environmental or endogenous factors, and considered a unit

Precommercial thinning: the removal of trees not for immediate financial return but to reduce stocking to concentrate growth of the more desirable trees

Pruning: the removal, close to branch or collar or flush with the stem, of side branches (live or dead) and multiple leaders from a standing tree – note pruning is generally done on plantations to improve the tree or its timber, or on urban and rural trees to improve their aesthetics or health

Pulpwood: roundwood, whole-tree chips, or wood residues that are used for the production of wood pulp




Regeneration: seedlings or saplings existing in a stand

Regeneration method: a cutting procedure by which a new age class is created; the major methods are clearcutting, seed tree, shelterwood, selection and coppice

Release: a treatment designed to free young trees from undesirable, usually overtopping, competing vegetation

Rhizome: A modified stem that grows below ground, commonly stores food materials, and produces roots, scale leaves, and suckers irregularly along its length and not just at nodes.

Root collar: the location on a plant where the primary vascular anatomy changes from that of a stem to that of a root

Rotation: in even-aged systems, the period between regeneration establishment and final cutting




Sapling: a usually young tree larger than a seedling but smaller than a pole

Sawlog: a log that meets minimum regional standards of diameter, length, and defect, intended for sawing

Sawtimber: trees or logs cut from trees with minimum diameter and length and with stem quality suitable for conversion to lumber. Hardwood trees larger than 11 inches dbh, and conifers larger than 9 inches dbh.

Seed bed: the soil or forest floor on which seed falls

Seed tree: a tree left standing for the sole or primary purpose of providing seeds

Seedling: a usually young tree smaller than a sapling, grown from a seed

Shade tolerance: the capacity of trees to grow satisfactorily in the shade of, and in competition with, other trees

Shelterwood: the cutting of most trees, leaving those needed to produce sufficient shade to produce a new age class in a moderated microenvironment

Shortwood: stem wood less than 120 inches in length

Silvics: the study of the life history and general characteristics of forest trees and stands, with particular reference to environmental factors, as a basis for the practice of silviculture

Silvicultural prescriptions: a planned series of treatments designed to change current stand structure to one that meets management goals -note the prescription normally considers ecological, economic, and societal constraints

Silvicultural system: a planned series of treatments for tending, harvesting, and re-establishing a stand - note the system named is based on the number of age classes (coppice, even-aged, two-aged, uneven-aged) or the regeneration method (clearcutting, shelterwood, selection, coppice, coppice with reserve) used

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

Single tree selection: 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

Site: the area in which a plant or stand grows, considered in terms of its environment, particularly as this determines the type and quality of the vegetation the area can carry - notes sites are classified either qualitatively, by their climate, soil, and vegetation, into site types, or quantitatively, by their potential wood production, into site classes

Site class: a classification of site quality, usually expressed in terms of ranges of dominant tree height at a given are or potential mean annual increment at culmination

Site index: a species-specific measure of actual or potential forest productivity (site quality, usually for even-aged stands), expressed in terms of the average height of trees included in a specified stand component (defined as a certain number of dominants, codominants, or the largest and tallest trees per unit area) at a specified index or basal area - note site index is used as an indicator of site quality

Site index curve: a curve showing the expected height growth pattern for trees of the specified stand component in even-aged stands of a given site index

Site preparation: hand or mechanized manipulation of site, designed to enhance the success of regeneration

Skidding: dragging trees or logs by means of a self-propelled machine

Slash: the residue, e.g., treetops and branches, left on the ground after logging are accumulating as a result of storm, fire girdling, or delimbing

Snag: a standing, generally unmerchantable dead tree from which the leaves and most of the branches have fallen

Square Foot: A unit of area equaling 144 square inches.

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

Stand density: a quantitative measure of stocking expressed either absolutely in terms of number of trees, basal area, or volume per unit area or relative to some standard condition

Stand structure: the horizontal or vertical distribution of a forest stand, including the height, diameter, crown layers, and stems of trees, shrubs, herbaceous understory, snags, and down woody debris

Stocking: an indication of growing-space occupancy relative to a preestablished standard

Stratification: the exposure of seed to a cold, moist treatment to overcome dormancy and promote germination

Stump Sprout : Regeneration of shoot growth from either adventitious or dormant buds from a cut tree stump

Succession: the gradual supplanting of one community of plants by another

Sucker (Root Sprout): Shoots arising from below ground level either from a rhizome or from a root

Sustainability: the capacity of forests, ranging from stands to ecoregions, to maintain their health, productivity, diversity, and overall integrity, in the long run, in the context of human activity and use




Tending: any treatment designed to enhance growth, quality, vigor, and composition of the stand after establishment or regeneration and prior to final harvest

Thinning: a cultural treatment made to reduce stand density of trees primarily to improve growth, enhance forest health, or recover material potential mortality

Two-aged stand: a growing area with trees of two distinct age classes separated in age by more than +/- 20 percent of rotation




Understory: all vegetation growing under an overstory

Uneven-aged stand: a stand with trees of three or more distinct age classes, either intimately mixed or in small groups




Variable retention harvest system: an approach to harvesting based on the retention of structural elements or biological legacies from the harvested stand for integration into the new stand to achieve various ecological objectives

Veneer: a thin sheet of wood of uniform thickness, produced by rotary cottoning (peeling) or slicing, and sometimes by sawing




Weeding: a release treatment in stands not past the sapling stage that eliminates or suppresses undesirable vegetation regardless of crown position Llink to Costs of different silvicultural treatments Link to Management for ecological objectives examples Link to Even-aged management examples Link to Key questions for managing red pine Link to Home Link to History of Red Pine Management Guide Link to contributors Link to Ecology Link to Site characteristics Link to Species characteristics Site map Link to Stand characteristics Link to Silviculture Site map Site map Site map Link to Managing for ecological objectives Link to Forest Health Link to Specific pest concerns Site map Link to Other resources Site map Link to Stumpage prices Link to Financial analysis of forest management investment options Link to Management examples Link to Glossary Link to Site map Link to References


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North Central Region Forest Management Guide: A cooperative project of the USDA Forest Service and University of Minnesota.
USDA Forest Service - Northern Research Station
Last Modified:  05/25/2006