Invalid Unit Specified
Subclass Detail Report: S17
Tropical Forest & Woodland Subclass

The U.S. National
Vegetation Classification
Tropical forests found at lowland and montane elevations including tropical dry forests, and lowland to montane humid forests (tropical rainforests) and tropical forested wetlands, where frost is essentially absent at sea level.
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Translated Name:Tropical Forest & Woodland Subclass
Colloquial Name:Tropical Forest & Woodland
Tropical Forest & Woodland varies from dry to humid forests, from sea level to montane elevations, and includes forested wetlands. Tropical dry forest (sometimes called Tropical Dry Forest & Woodland or Tropical Seasonally Dry Forest) range in canopy types, including evergreen, semi-evergreen (needle-leaved or broad-leaved), or largely or wholly deciduous. Tree growth forms predominate and may be species-rich, with micro- to mesophyll leaves, but succulent species may be present. It occurs in humid dry tropical climates with a pronounced dry season, during which some or all of the trees may lose their leaves, or leaves may be moderately small and evergreen sclerophyllous. Canopy heights decrease and canopy coverage tends to decrease as the climate dries until the forests are reduced to open, short-statured (5-15 m) woodlands.

Tropical humid forests (including moist and wet forests) occur in the humid tropics where rainfall varies from abundant and well-distributed throughout the year to somewhat seasonal. Tree growth forms predominate, are tall, often of numerous species, some with buttressed bases, often smooth bark, and evergreen meso- to macrophyll leaves. Also present may be tree ferns, large woody climbers or lianas, and both vascular and nonvascular epiphytes, often of greater diversity than the ground layer. Heights may exceed 30 m. Tropical forested wetlands include swamps and mangroves, where soils are seasonally or permanently saturated to inundated by freshwater or saltwater, with hydrophytic plants and, in the case of mangrove, distinctive hydromorphic growth forms adapted to saline conditions.
Tropical Forest & Woodland is dominated by broad-leaved, often megaphyll, evergreen trees, broad-leaved drought-deciduous or semi-deciduous trees, or small-leaved (micro- to mesophyll evergreen trees). Evergreen needle-leaved trees may occur in association with these other growth forms. Climates are consistently warm (seasonal daily temperatures with minimal variation), and annual rainfall is typically >100 cm.
Vegetation Hierarchy
Name:Database Code:Classification Code:
Class 1 Forest & Woodland C01 1
Subclass 1.A Tropical Forest & Woodland S17 1.A
Formation 1.A.5 Mangrove F006 1.A.5
Formation 1.A.2 Tropical Lowland Humid Forest F020 1.A.2
Formation 1.A.3 Tropical Montane Humid Forest F004 1.A.3
Formation 1.A.4 Tropical Flooded & Swamp Forest F029 1.A.4
Formation 1.A.1 Tropical Dry Forest & Woodland F003 1.A.1
Review of tropical monsoon forests is needed, as they can vary from dry to moist.
Synonomy: = Tropical Forest & Woodland (Holzman 2008)

Related Type Name:

Short Citation:
  • Brady and Weil 2002
  • Faber-Langendoen et al. 2015c
  • Holdridge 1967
  • Holzman 2008
  • Soil Survey Staff 1999
  • Whittaker 1975
States/Provinces:
Nations:US
Range:Tropical Forest & Woodland is concentrated around the equator with tropical humid forest most common between 0° and 10°N and S latitude, and tropical dry forest between 10° and 23°N and S, with latitudinal limits shaped by frost and drought. Tropical Forest & Woodland is found in three major regions: South and Central America and the Caribbean Islands; Africa (west, central, and interior) and Madagascar; and the Indo-Asian Pacific (India, Southeast Asia, Indonesia, New Guinea, Pacific Islands, and northeastern Australia).
US Forest Service Ecoregions
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Division Name:
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Section Name:
Section Code:     Occurrence Status:
Tropical Dry Forest (typically called Tropical Dry Forest or Tropical Seasonally Dry Forest) range in canopy types, including evergreen, semi-evergreen (needle-leaved or broad-leaved), or largely or wholly deciduous Canopy heights decrease and canopy coverage tends to decrease as the climate dries until the forests are reduced to open, short-statured (5-15 m) woodlands (Whittaker 1975). Tree growth forms predominate, with micro- to mesophyll leaves, but succulent species may be present. They occur in humid dry tropical climates, typically with a pronounced dry season, during which some or all of the trees may lose their leaves, or leaves may be moderately small and evergreen sclerophyllous. Some tropical forests have a more sustained dry period, with less seasonality.

Tropical humid forests (including moist and wet forests) occur in the humid tropics where rainfall varies from abundant and well-distributed throughout the year to somewhat seasonal. Tree growth forms predominate, are tall, often of numerous species, some with buttressed bases, often smooth bark, and evergreen meso- to macrophyll leaves. Also present may be tree ferns, large woody climbers or lianas, and both vascular and nonvascular epiphytes, often of greater diversity than the ground layer. Heights may exceed 30 m (Whittaker 1975).

Tropical forested wetlands include swamps and mangroves, with hydrophytic plants and, in the case of mangrove, distinctive hydromorphic growth forms adapted to saline conditions.
Climate: In general, the tropical humid forest has a fairly consistent average annual temperature, ranging from 26-27°C, and a more variable daily temperature, with changes up to 5°C. In the tropical dry forest, average annual temperatures range between 20° and 30°C, and daily temperatures change from between 26° to 28°C. At sea level, frost is essentially absent from Tropical Forest & Woodland (Holdridge 1967). Rainfall ranges from 100 to 450 cm (400-180 inches), with the rainfall becoming increasingly more seasonal in tropical dry climates, where the dry season may extend for 4-7 months (Holzman 2008).

Soil/substrate/hydrology: Soils in humid regions are often highly weathered ancient soils with high acidity and low nutrient and organic matter content; however, many tropical forests occur on rich volcanic or limestone soils. The major soil orders in the U.S. system include Oxisols, Ultisols, Inceptisols, and Entisols (Soil Survey Staff 1999) [see Brady and Weil (2002) for comparison of U.S. soil orders with Canadian and FAO systems]. Younger and richer soils are found in alluvial habitats or in areas influenced by ashes from volcanic activity (Holzman 2008).
High
No Data Available
Authors:
D. Faber-Langendoen and E. Helmer      Version Date: 02Aug2016


References:
  • Brady, N. C., and R. R. Weil. 2002. The nature and properties of soils. Thirteenth edition. Prentice Hall, Upper Saddle River, NJ.
  • Faber-Langendoen, D., T. Keeler-Wolf, D. Meidinger, C. Josse, A. Weakley, D. Tart, G. Navarro, B. Hoagland, S. Ponomarenko, J.-P. Saucier, G. Fults, and E. Helmer. 2015c. Classification and description of world formation types. General Technical Report RMRS-GTR-000. USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO.
  • Holdridge, L. R. 1967. Life Zone Ecology. Tropical Science Center, San Jose, Costa Rica.
  • Holzman, B. A. 2008. Tropical forest & woodland biomes. Greenwood guide to biomes of the world. S. L. Woodward, general editor. Greenwood Press, Westport, CT.
  • Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. Second edition. USDA Natural Resources Conservation Service, Washington, DC.
  • Whittaker, R. H. 1975. Communities and ecosystems. Second edition. Macmillan Publishing Co., New York. 387 pp.


USNVC Credits: Detailed Description of the National Vegetation Classification Types

Date Accessed:

To cite a description:
Author(s). publicationYear. Description Title [last revised revisionDate]. United States National Vegetation Classification. Federal Geographic Data Committee, Washington, D.C.

About spatial standards:
The United States Federal Geographic Data Committee (hereafter called the FGDC) is tasked to develop geospatial data standards that will enable sharing of spatial data among producers and users and support the growing National Spatial Data Infrastructure (NSDI), acting under the Office of Management Budget (OMB) Circular A-16 (OMB 1990, 2000) and Executive Order #12906 (Clinton 1994) as amended by Executive Order #13286 (Bush 2003). FGDC subcommittees and working groups, in consultation and cooperation with state, local, tribal, private, academic, and international communities, develop standards for the content, quality, and transferability of geospatial data. FGDC standards are developed through a structured process, integrated with one another to the extent possible, supportable by the current vendor community (but are independent of specific technologies), and publicly available.

About this document
This document contains type descriptions at the Subclass level of the U.S. National Vegetation Classification. These descriptions were primarily written by NatureServe ecologists in collaboration with Federal Geographic Data Committee Vegetation Subcommittee and a wide variety of state, federal and private partners as a part of the implementation of the National Vegetation Classification. Formation descriptions were written by the Hierarchy Revisions Working Group. The descriptions are based on consultation with natural resource professionals, published literature, and other vegetation classification systems. The Ecological Society of America's Panel on Vegetation Classification is responsible for managing the review and formal adoption of these types into the National Vegetation Classification. Partners involved in the implementation of the USNVC include:

U.S. Government
  • Department of Agriculture (USDA)
  • Department of Commerce (DOC)
  • Department of Defense (DOD)
  • Department of the Interior (USDI)
  • Forest Service (FS) - Chair
  • National Agriculture Statistical Service (NASS)
  • Natural Resources Conservation Service (NRCS)
  • National Oceanic and Atmospheric Administration (NOAA)
  • National Marine Fisheries Service (NMFS)
  • U.S. Army Corps of Engineers (USACE)
  • U.S. Navy (NAVY)
  • Bureau of Land Management (BLM)
  • Fish and Wildlife Service (FWS)
  • National Park Service (NPS)
  • U.S. Geological Survey (USGS)
  • Environmental Protection Agency (EPA)
  • National Aeronautics and Space Administration (NASA)
Non U.S. Government
  • NatureServe (NS)
  • Ecological Society of America (ESA)

Disclaimer:
Given the dynamic nature of the standard, it is possible a type description is incomplete or in revision at the time of download; therefore, users of the data should track the date of access and read the revisions section of the USNVC.org website to understand the current status of the classification. While USNVC data have undergone substantial review prior to posting, it is possible that some errors or inaccuracies have remained undetected.

For information on the process used to develop these descriptions see:

Faber-Langendoen, D., T. Keeler-Wolf, D. Meidinger, D. Tart, B. Hoagland, C. Josse, G. Navarro, S. Ponomarenko, J.-P. Saucier, A. Weakley, P. Comer. 2014. EcoVeg: A new approach to vegetation description and classification. Ecological Monographs 84:533-561 (erratum 85:473).

Franklin, S., D. Faber-Langendoen, M. Jennings, T. Keeler-Wolf, O. Loucks, A. McKerrow, R.K. Peet, and D. Roberts. 2012. Building the United States National Vegetation Classification. Annali di Botanica 2: 1-9.

Jennings, M. D., D. Faber-Langendoen, O. L. Louckes, R. K. Peet, and D. Roberts. 2009. Standards for associations and alliances of the U.S. National Vegetation Classification. Ecological Monographs 79(2):173-199.

FGDC [Federal Geographic Data Committee]. 2008. Vegetation Classification Standard, FGDC-STD-005, Version 2. Washington, DC., USA. [http://www.fgdc.gov/standards/projects/FGDC-standards-projects/vegetation/NVCS_V2_FINAL_2008-02.pdf]

For additional information contact:

  • Implementation of the U.S. National Vegetation Classification Standard - Alexa McKerrow (amckerrow@usgs.gov)
  • NatureServe's Development of NVC Type Descriptions - Don Faber-Langendoen (don_faber- langendoen@natureserve.org)
  • Ecological Society of America's Review of the Type Descriptions Scott.Franklin@unco.edu
  • Federal Geographic Data Committee - Vegetation Subcommittee's Activities - Marianne Burke (mburke@fs.fed.us)