EPA's Report on the Environment

Definitions of Land Cover Categories


Developed

Areas characterized by a high percentage (30% or more) of constructed materials (e.g., asphalt, concrete, buildings).

  • Developed, low intensity. Areas with a mixture of constructed materials and vegetation. Impervious surfaces account for 20% to 49% percent of total cover. These areas most commonly include single-family housing units.
  • Developed, medium intensity. Areas with a mixture of constructed materials and vegetation. Impervious surfaces account for 50% to 79% of the total cover. These areas most commonly include single-family housing units.
  • Developed, high intensity. Highly developed areas where people reside or work in high numbers. Examples include apartment complexes, row houses, and commercial/industrial space. Impervious surfaces account for 80% to 100% of the total cover.
  • Developed, open space. Areas with a mixture of some constructed materials, but mostly vegetation in the form of lawn grasses. Impervious surfaces account for less than 20% of total cover. These areas most commonly include large-lot single-family housing units, parks, golf courses, and vegetation planted in developed settings for recreation, erosion control, or aesthetic purposes.

Agriculture (Planted/Cultivated)

Areas characterized by herbaceous vegetation that has been planted or is intensively managed to produce food, feed, or fiber, or is maintained in developed settings for specific purposes. Herbaceous vegetation accounts for 75% to 100% of the cover.

  • Pasture/hay. Areas of grasses, legumes, or grass-legume mixtures planted for livestock grazing or the production of seed or hay crops, typically on a perennial cycle. Pasture/hay vegetation accounts for more than 20% of total vegetation.
  • Cultivated crops. Areas used for the production of annual crops, such as corn, soybeans, vegetables, tobacco, and cotton, and also perennial woody crops such as orchards and vineyards. Crop vegetation accounts for more than 20% of total vegetation. This class also includes all land being actively tilled.

Shrubland

Areas characterized by natural or semi-natural woody vegetation with aerial stems, generally less than 6 meters tall, with individuals or clumps not touching to interlocking. Both evergreen and deciduous species of true shrubs, young trees, and trees or shrubs that are small or stunted because of environmental conditions are included.

  • Shrubland (shrub/scrub). Areas dominated by shrubs less than 5 meters tall, with shrub canopy typically more than 20% of total vegetation. This class includes true shrubs, young trees in an early successional stage, and trees stunted from environmental conditions.

Grassland/Herbaceous

Areas characterized by natural or semi-natural herbaceous vegetation; herbaceous vegetation accounts for 75% to 100% of the cover.

  • Grassland/herbaceous. Areas dominated by gramanoid or herbaceous vegetation, which generally accounts for more than 80% of total vegetation. These areas are not subject to intensive management such as tilling, but can be used for grazing.

Forest

Areas characterized by tree cover (natural or semi-natural woody vegetation, generally more than 6 meters tall); tree canopy accounts for 25% to 100% of the cover.

  • Deciduous forest. Areas dominated by trees generally more than 5 meters tall, accounting for more than 20% of total vegetation cover. More than 75% of the tree species shed foliage simultaneously in response to seasonal change.
  • Evergreen forest. Areas dominated by trees generally more than 5 meters tall, accounting for more than 20% of total vegetation cover. More than 75% of the tree species maintain their leaves all year. Canopy is never without green foliage.
  • Mixed forest. Areas dominated by trees generally more than 5 meters tall, accounting for more than 20% of total vegetation cover. Neither deciduous nor evergreen species are more than 75% of total tree cover.

Wetland

Areas where the soil or substrate is periodically saturated with or covered by water as defined by Cowardin et al. (1979).

  • Woody wetlands. Areas where forest or shrubland vegetation accounts for more than 20% of vegetative cover and the soil or substrate is periodically saturated with or covered by water.
  • Emergent herbaceous wetlands. Areas where perennial herbaceous vegetation accounts for more than 80% of vegetative cover and the soil or substrate is periodically saturated with or covered by water.

Ice/Snow (Perennial)

Areas characterized by a perennial cover of ice and/or snow, generally more than 25% of total cover.

Barren (Rock/Sand/Clay)

Areas of bedrock, desert pavement, scarps, talus, slides, volcanic material, glacial debris, sand dunes, strip mines, gravel pits, and other accumulations of earthen material. Generally, vegetation accounts for less than 15% of total cover.

Open Water

Areas of open water, generally with less than 25% cover of vegetation or soil.

Sources

Definitions adapted from National Land Cover Database 2006 (NLCD 2006) product legend. http://www.mrlc.gov/nlcd06_leg.php.

Wetland definition based on: Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the U.S. U.S. Department of the Interior, Fish and Wildlife Service. FWS/OBS-79/31.

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