Acres of Forest Land Converted to Developed Land, 1982-1997
Description
This dot density map shows the total acreage of
forest land converted to developed land from
1982 to 1997. Dots are aggregated by and placed
randomly within 8-digit hydrologic units. Each
red dot represents 2,000 acres of forest land
converted to developed land. Developed land is a
combination of urban and built-up areas and
rural transportation land. There were 10,279,200
acres of land converted to developed land from
1982 to 1997. Areas with 95% or more Federal
area are shaded gray.
Cautions for this Product:
Use this map only to identify broad spatial
trends. Within an 8-digit hydrologic unit, dot
counts represent total acreage, with an error of
plus or minus one dot to account for remainders.
Data are not available for Alaska or the Pacific
Basin. Data for Puerto Rico and the U.S. Virgin
Islands are aggregated by 6-digit hydrologic
unit.
Sources
Source:
National Resources Inventory, 1997
Distributor:
USDA-NRCS-RIAD
Reliability:
NRI sample data are generally reliable at the
95% confidence interval for state and certain
broad substate area analyses. Generally,
analyses that aggregate data points by smaller
geographic areas and/or more specific criteria
result in fewer data points for each aggregation
and therefore less reliable estimates. NRI maps
reflect national patterns rather than site-
specific information.
Layers
Aggregate Layer:
Cross of State with 8 Digit Hydrologic Units and
Federal Land
Other Layers Displayed:
States, Rivers
Definitions
Developed land:
A combination of land cover/use categories,
Urban and built-up areas, and Rural
Transportation Land.
Forest land:
A Land Cover/Use that is at least 10 percent
stocked by single stemmed forest trees of any
size which will be at least 4 meters (13 feet)
tall at maturity. When viewed vertically,
canopy cover is 25 percent or greater. Also
included are areas bearing evidence of natural
regeneration of tree cover (cutover forest or
abandoned farmland) and not currently developed
for nonforest use. For classification as forest
land, an area must be at least one acre and 100
feet wide. [NRI-97]
Rural transportation land:
A Land Cover/Use category which consists of all
highways, roads, railroads and associated rights-
of-way outside urban and built-up areas;
including private roads to farmsteads or ranch
headquarters, logging roads, and other private
roads, except field lanes. [NRI-97]
Urban and built-up areas:
A Land Cover/Use category consisting of
residential, industrial, commercial, and
institutional land; construction sites; public
administrative sites; railroad yards;
cemeteries; airports; golf courses; sanitary
landfills; sewage treatment plants; water
control structures and spillways; other land
used for such purposes; small parks (less than
10 acres) within urban and built-up areas; and
highways, railroads, and other transportation
facilities if they are surrounded by urban
areas. Also included are tracts of less than 10
acres that do not meet the above definition but
are completely surrounded by Urban and Built-up
land. Two size categories are recognized in the
NRI: (i) areas 0.25 to 10 acres, and (ii) areas
greater than 10 acres. [NRI-97]
Product Information
Product ID:
5104
Production Date:
11/22/99
Product Type:
Map
For additional information
contact the Resources Inventory and Assessment Division.
Please include the Product ID you are inquiring about.
nri@wdc.usda.gov
or 1400 Independence Avenue SW - P.O. Box 2890 -
Washington D.C. 20013. If you use our analysis products,
please be aware of our disclaimer.
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