Definitions
Advance regeneration: small trees that appear before any silvicultural practice is
undertakes to establish new growth.
Age class: a distinct aggregation of trees of more or less similar age originating from a
single natural disturbance or regeneration cutting.
Angiosperm: member of the class Angiospermae, including flowering plants with ovules
(seeds) enclosed in an ovary (fruit). Members include oak, pecan, aspen, cottonwood,
mahogany, and also referred to as ‘hardwoods’.
Basal area: the cross-sectional area of tree stems at a standard height (usually 4.5 ft); the
total of such values on a per unit area basis (= stand basal area) is a stand attribute widely
used in stocking and thinning guides.
Biome: an extensive community of plants and animals determined by soils and climate;
an ecosystem.
CAI: current annual increment. Growth rate per year at a specified point in time.
Clearcutting method: a method of regeneration an even-aged stand in which a new age
class develops in a fully exposed microclimate after removal, in a single cutting, of all
trees in the previous stand. Regeneration may be from natural seeding, direct seeding,
planted seedlings, or advance reproduction. Harvesting may be done in groups or patches
(group or patch clearcutting) on in strips (Strip clearcutting). In the clearcutting system,
the management unit or stand consists of the individual clearcut stand.
Clone: a group of individuals of identical genotype, usually arising from vegetative
propagation.
Commercial thinning: a thinning in which the trees removed have value at least equal to
the cost of harvest.
Conifer: a cone bearing plant. Member of the class Gymnospermae. Also, called
softwood species.
Conservation Reserve Program (CRP): a federal program to convert highly erodible
crop land to trees, grass or wildlife habitat through incentives that include cost sharing
and annual payments, usually over a 10-year period.
Board foot: a volumetric measure of lumber or logs that will be milled into lumber = 1 ft
long x 1 ft wide x 1 in thick.
Cord: unit of volumetric measure for pulpwood, equal to 128 cu. ft loosely stacked or 90
solid cu. ft of wood and bark. One cord equals 0.495 MBF Doyle scale. One cord of
hardwood equals about 2 tons or 1,000 to 2,000 lb paper or 2,700 copies of a daily
newspaper.
D.B.H.: diameter breast height, diameter of a standing tree, measured at 4.5 ft (1.35 m)
above ground.
Density: number of individuals per unit area (ecology); any measure expressing degree of
competition (forestry).
Doyle scale: volumetric scaling rule for log purchase calculated by the formula:
bd ft = ((D-4)/4)2 x L,
where D = log diameter in inches, and L is log length in feet. This scale gives an
approximate indication of the number of lumber board feet that can be sawed from a
roughly cylindrical log.
Ecology: the study of relations between plants and animals and their environment.
Ecosystem: a distinguishable community of plants and animals interacting with the
physical factors of its environment.
Even-aged stand: a stand of trees containing a single age class.
Forest: an area supporting trees, ordinarily including multiple ages, species, and
conditions.
Forest management: the practical application of scientific, economic, and social
principles to the administration and working of a forest property for specified objectives.
Forestry Incentives Program (FIP): a federal cost-sharing program for approved forest
management practices such as site preparation, planting and timber stand improvement.
Private owners of at least 10 acres but normally no more than a total of 1,000 acres of
eligible forest land may apply. The total cost share payments cannot exceed $10,000
annually but are usually much less.
Genotype: the genetic composition of an individual organism.
Group selection method: a method of regenerating uneven-aged stands in which trees
are removed and new age classes established in small groups. Maximum width of groups
is approximately twice the height of mature trees. The management unit or stand in which
regeneration, growth, and yield are regulated is an aggregation of such groups.
Gymnosperm: member of the class Gymnospermae; seed plants with ovules (seeds)
borne on open scales of cones. Examples include pines, spruces, junipers, ginkgo, and
collectively referred to as softwoods.
Intolerant: lacking the ability to grow in shade of or in competition with other and taller
plants.
Lumber grades: based on number of defects and overall quality, in decreasing order of
quality, lumber grades are: FAS- first and seconds, 1F, one face clear, 1C- one common,
2C- two common, 3A- grade 3, BG- below grade, not graded for quality.
MAI: mean annual increment is the average growth rate of a stand up to a specified point
in time. Calculated as the sum of present volume plus volume of any thinnings, divided
by age.
MBF: one thousand board feet.
MCF: one thousand cubic feet.
Natural regeneration method: a method of establishing forest stands in which the trees
grow from natural seedfall or sprouting.
Nonindustrial private landowner: private landowners who hold timber as an investment
or as part of a larger privately help business such as a farm.
Old growth: a stage in stand development characterized by advanced age, large trees,
layered structure, and abundant woody debris. Usually applied to stands that have had no
human intervention.
PAI: periodic annual increment is an approximation to current annual increment (most
commonly in volume), calculated as the difference between measurements at two points
in time, divided by number of years between the two measurements.
Peelers: logs designated for conversion into plywood.
Post-consumer recovered paper: newspapers, cardboard, magazines, office paper.
Precommercial thinning: an early thinning removing trees too small to have commercial
value, usually done to improve spacing; also referred to as ‘respacing’.
Post-consumer recovered paper: trimmings and scraps recovered before reaching the
consumer.
Pulpwood: roundwood greater than 4 in in diameter on the small end, cut into lengths of
5 ft 6 in; used in the manufacture of pulp and paper products.
Rain Forest: Evergreen forest (conifer or angiosperm) with high rainfall and little or no
dry period.
Regeneration: newly established plants (synonym = reproduction), or the process by
which new plants are established.
Rotation: one cycle of a forest stand from planting until final harvest.
Roundwood: round logs or tree sections harvested for use in the forest products industry.
Sawlogs: logs greater than 12 in (small end diameter) designated for processing in a
sawmill.
Second growth: the forest that replaced the virgin forests that once covered the region. In
some regions of the SE US, the second growth has been cut, and the third or even fourth
forest is in the process of being harvested.
Seed-tree method: an even-aged regeneration method in which a new age class develops
from seedlings that germinate in fully exposed microenvironments after removal of all
the previous stand except a small number of trees left to provide seed. Seed trees are
removed after regeneration is established.
Selection method: a collective term for the single tree selection and group selection
methods. A silvicultural system involving removal of individual trees (single tree) or
scattered groups (group) of trees at frequent intervals, leading to an uneven-aged
condition.
Selective cutting: a loose term for any form of cutting that removes only part of a stand.
Often incorrectly used as a synonym for selection system. Undesirable term because of
confusion introduced by past use of the term for destructive high-grading practices.
Shelterwood method: a method of regenerating an even-aged stand in which a new age
class develops beneath the partially shaded micorenvironment provided by the residual
trees (overstory). Harvesting may be done uniformly throughout the stand, in groups or
patches, or in strips. The overstory is removed once the regeneration is established.
Silvicultural system: a planned program of silvicultural treatment over the live of a stand,
extending from regeneration through intermediate operations to harvest and regeneration.
Silviculture: the body of techniques used to manipulate stand environments and direct
stand and tree development to create or maintain desired conditions.
Single-tree selection: method: a method of creating new age classes in uneven-aged
stands in which individual trees of all size classes are removed more or less uniformly
throughout the stand to achieve desired stand structural characteristics.
Site preparation: a collective term for various measures that can be taken to alleviate
conditions unfavorable to prompt and adequate regeneration.
Slash: the residue of tops, branches, and other unused material left on the ground after
harvest.
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 management: the practical application of scientific and economic knowledge
through silvicultural measures designed to direct development of a stand toward desired
objectives.
Stocking density: a measure of the total number of trees per unit area.
Sustainable level: the level or rate of production or economic expansion that can be
maintained without causing instability to occur in markets or production processes.
Stumpage: a collective term for the trees standing in the forest before harvest.
Stumpage price: the price received for trees standing in the forest. The price is usually
broken out by product class.
Thinning: removal of a portion of trees in a stand to promote development of the
remaining trees and vegetation and to secure income prior to final harvest, while retaining
the even-aged character of the stand.
Tolerant: having the ability to become established and grow under shade of or in
competition with taller plants.
Tree: a woody perennial at least 10 ft tall, usually with one main stem.
Veneer: thin sheets of wood peeled from peeler logs used in the manufacture of plywood.