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Acre
- A unit of area that contains 43,560 square feet.
Aspect - The direction of
drainage for most of the plot, recorded as the azimuth of this direction.
0 indicates no slope.
Aspect Classes
North 337.6 - 22.5 degrees
Northeast 22.6 - 67.5 degrees
East 67.6 - 112.5 degrees
Southeast 112.6 - 157.5 degrees
South 157.6 - 202.5 degrees
Southwest 202.6 - 247.5 degrees
West 247.6 - 292.5 degrees
Northwest 292.6 - 337.5 degrees
Average annual mortality - The
average volume of either growing-stock or sawtimber that died in one year
of natural causes for the time period between two successive forest
inventories. In the western states, this variable represents the annual
mortality at the time of the current inventory.
Average net annual growth - The
average change in volume of either growing-stock or sawtimber in one year
for the time period between two successive forest inventories minus the
average annual volume lost to mortality from natural causes (average
annual mortality). In the western states, this variable represents the
annual growth at the time of the current inventory.
Average annual removals - The
average volume of either growing-stock or sawtimber removed from the
inventory in one year by harvesting, cultural operations (such as
timber-stand improvement), land clearing, or changes in land use for the
time period between two successive forest inventories. Not avaiable for
the western states.
Board foot - A measure of product potential that relates to
the amount of lumber that is 1 foot long, 1 foot wide, and 1 inch thick
(or the equivalent) that can be obtained from a tree. Board foot in these
tables are reported using the international 1/4-inch rule.
Central stem - The portion of a tree between a 1-foot stump
and the minimum 4.0-inch top diameter outside bark, or point where the
central stem breaks into limbs.
Commercial species - Tree species presently or
prospectively suitable for industrial wood products. (Note: Excludes
species of typically small size, poor form, or inferior quality such as
sourwood, osage-orange, redbud, mountain-mahogany, and mesquite.)
County - Name of political divisions (counties, parishes,
or other similar governmental units) in a State.
Crown class - A tree classification that primarily reflects
the amount of sunlight received rather than the conventional "crown
position" found in forestry textbooks:
|
Crown class |
Definition |
| Open
grown |
Trees
with crowns that have received full light from above and from all
sides throughout all or most of their life, particularly during
early development. |
| Dominant |
Trees
with crowns extending above the general level of the canopy and
receiving full light from above and partly from the sides; larger
than the average trees in the stand, and with crowns well
developed, but possibly somewhat crowded on the sides. |
| Codominant |
Trees
with crowns forming part of the general level of the canopy and
receiving full light from above, but comparatively little from the
side—usually with medium size crowns more or less crowded on the
sides. |
| Intermediate |
Trees
shorter than those in the preceding two classes, but with crowns
either below or extending into the canopy formed by the dominant
and codominant trees, receiving little direct light from above,
and none from the sides; usually with small crowns very crowded on
the sides. |
| Overtopped |
Trees
with crowns entirely below the general level of the canopy and
receiving no direct light either from above or the sides. |
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Cubic foot
- A measure of volume that relates to an amount of wood that is 1 foot
long, 1 foot wide, and 1 foot thick (or the equivalent).
Date of inventory - A dating of a
State's forest inventory based on the calendar year in which most of a
State's inventory data were collected. Data variables prefixed with
"past" refer to data from the inventory prior to the dated
inventory.
Damage - Damage is recorded for live trees if the presence
of damage or pathogen activity is serious enough to reduce the quality or
vigor of the tree. When a tree is damaged by more than one agent, the most
severe damage is coded. Damage recorded for dead trees is the cause of
death.
Forest Type - A classification of
forest land in which the named species, either singly or in combination,
comprise a plurality of live tree stocking. These types are based on a
standard set of local forest types in the Forest Service Handbook, and
have been logically organized into broader forest type groups to
facilitate reporting.
Growing-stock tree - Live
timberland trees of commercial species that in the East contain at least
one 12-foot saw log or two saw logs 8 feet or longer, or that in the West
contain at least one 8-foot saw log, now or prospectively, and meet
specified standards of size, quality, and merchantability. (Note: Excludes
rough, rotten, and dead trees.)
Hardwoods - Dicotyledonous trees, usually broad-leaved and
deciduous.
Hard hardwoods - Hardwood species
with an average specific gravity greater than 0.50, such as oaks,
hickories, or hard maples.
International 1/4-inch rule - A
log rule or formula for estimating the board foot volume of logs, allowing
1/2 inch of taper for each 4-foot length and 1/4 inch of kerf.
Land use class - A classification
that indicates the basic biological potential of the land and its current
use and legal status. Initially, land is broken into two broad classes
(forest and nonforest). These broad classes are then separated into the
more specific classes.
| Land
class |
Definition |
| Forest
Land |
Land
currently growing forest trees of any size with a total stocking
value of at least 16.7 (10 base 100 in the West), or lands
formerly forested, currently capable of becoming forest land, and
not currently developed for nonforest uses. These lands must be a
minimum of 1 acre in area. Roadside, streamside, and shelterbelt
strips of timber must have a crown width of at least 120 feet to
qualify as forest land. Unimproved roads, trails, streams, and
clearings within forest areas are classified as forest land if
they are less than 120 feet wide. Recently clearcut areas that are
currently nonstocked are classed as forest land unless they are
being used for a nonforest use such as agriculture. Forest land is
divided into two categories (timberland and other forest land),
and both of these categories may be further classified as reserved
if harvesting of trees is prohibited by statutory or
administrative restrictions.
|
| Timberland |
Forest
land that is producing, or capable of producing, in excess of 20
cubic feet per acre per year of industrial roundwood products, and
is not withdrawn from timber utilization by statute or
administrative regulation.
|
| Other
Forest Land |
Forest
land not capable of producing crops of industrial wood. This may
be the result of adverse site conditions such as sterile soils,
dry climate, poor drainage, high elevation, and rockiness. Trees
on these sites are usually of poor form, small size, or inferior
quality and consequently are not used for industrial products.
These sites often contain tree species that are not currently used
for industrial wood production.
|
| Reserved
Timberland |
Timberland
that has statutory or administrative restrictions prohibiting the
harvest of trees. Examples include land within the National
Wilderness Preservation System, Research Natural Areas, National
Parks and Monuments, and State Parks. In National Forests,
reserved forest lands are referred to collectively as withdrawn
forest land.
|
| Nonforest
Land |
Nonforest
Land Land that has never supported forests or land formerly
forested but now developed for uses such as agriculture,
residence, commerce, industry, city parks, or improved roads. If
located within forest areas, unimproved roads and nonforested
strips must be more than 120 feet wide, and clearings and other
openings in a forest area must be more than 1 acre to qualify as
nonforest land. Nonforest land also includes streams, sloughs,
estuaries, and canals more than 120 feet wide but less than one-
eighth of a mile (660 feet) wide, or lakes, reservoirs, and ponds
1 to 40 acres in size. |
Live trees - All living
trees. Included are all size classes, all tree classes, and both
commercial and noncommercial species.
Merchantable sections - Refers to
sections of the central stem of growing-stock trees that meet either
pulpwood or saw-log specifications.
Net volume - Gross volume less
deductions for rot, sweep, or other defects affecting use for roundwood
products.
Noncommercial species - Trees
species of typically small size, poor form, or inferior quality that
normally do not develop into trees suitable for industrial roundwood
products. Classified in volume tables as rough trees. Includes those
western species classified as woodland hardwoods in the Westwide data
base.
Ownership - A classification of
forest land based on the legal owner at the time of the current inventory.
Also indicates private lands leased to forest industry.
Rotten cull tree - Live trees of
commercial species that in the East do not contain at least one 12-foot
saw log or two saw logs 8 feet or longer, or that in the West do not
contain at least one 8-foot saw log, now or prospectively, and/or do not
meet regional specifications for freedom from defect primarily because of
rot; that is, when more than 50 percent (66 percent at the Southeastern
Station) of the cull volume in a tree is rotten.
Rough cull tree - Live trees of
commercial species that in the East do not contain at least one 12-foot
saw log or two saw logs 8 feet or longer, or that in the West do not
contain at least one 8-foot sawlog, now or prospectively, and/or do not
meet regional specifications for freedom from defect primarily because of
roughness or poor form. Includes all trees of noncommercial species in the
East and all trees classed as woodland hardwoods or woodland softwoods in
the Westwide data base.
Salvable dead trees - Standing or
downed dead trees that were formerly growing stock and are considered
merchantable. Trees must be at least 5.0 inches in diameter to
qualify.
Saw-log portion - That portion of
the central stem of sawtimber trees between the stump and the saw-log
top.
Saw-log top - The point on the
central stem of sawtimber trees above which a saw log can not be produced.
The minimum saw-log top is 7.0 inches d.o.b. for softwoods and 9.0 inches
d.o.b. for hardwoods.
Sawtimber tree - A growing-stock
tree that in the East contains at least a 12-foot saw log or two
noncontiguous saw logs 8 feet or longer, or that in the West contains at
least an 8-foot saw log, and meets regional specifications for freedom
from defect. Softwoods must be at least 9.0 inches diameter and hardwoods
must be at least 11.0 inches diameter
Select red oaks - A group of
several red oak species composed of cherrybark, Shumard, and northern red
oaks. Other red oak species are included in the"other red oaks"
group.
Select white oaks - A group of
several white oak species composed of white, swamp chestnut, swamp white,
chinkapin, Durand, and bur oaks. Other white oak species are included in
the "other white oaks" group.
Site class - A classification of
forest land in terms of inherent capacity to grow crops of industrial
wood. The class identifies the average potential growth in cubic
feet/acre/year (trees 5 inches diameter or larger to a 4-inch top) and is
based on the culmination of mean annual increment of fully stocked natural
stands.
Tree - A woody plant usually
having one or more perennial stems, a more or less definitely formed crown
of foliage, and a height of al least 12 feet at maturity.
Tree class - A classification of a
tree based on its general quality. For cut, dead, and salvable dead trees,
tree class reflects conditions at the time the tree died or was cut.
Survey unit - Forest Inventory
and Analysis survey unit, a multicounty division of a State based on broad
geo/physical characteristics of the land used primarily for reporting
purposes.
Timber class - A breakdown of
inventory volume in live and salvable dead trees by tree size and tree
class.
Upper stem portion - That portion
of the central stem of sawtimber trees between the saw-log top and the
minimum top diameter of 4.0 inches outside bark, or to the point where the
central stem breaks into limbs.
Volume of growing stock - The net
volume in cubic feet of growing-stock trees at least 5.0 inches in
diameter from a 1-foot stump to a minimum 4.0-inch top d.o.b. of the
central stem or to the point where the central stem breaks into
limbs.
Volume of live trees - The net
volume in cubic feet of growing-stock, rough, and rotten trees at least
5.0 inches in diameter from a 1-foot stump to a minimum 4.0-inch top d.o.b.
of the central stem or to the point where the central stem breaks into
limbs. For pinyon - juniper and noncommercial species in the west, volume
is calculated on all trees with a d.r.c. of 3 inches or larger.
Volume of sawlog portion of sawtimber
- The net volume in cubic-feet of the sawlog portion of sawtimber
trees.
Volume of sawtimber - The net
volume in board feet (International 1/4-inch rule) of the sawlog portion
of sawtimber trees.
Volume of timber - The net volume
in cubic feet of growing-stock, rough, rotten, and salvable dead trees at
least 5.0 inches in diameter from a 1-foot stump to a minimum 4.0-inch top
d.o.b. of the central stem or to the point where the central stem breaks
into limbs.
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