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Class Detail Report: C01
Mesomorphic Tree Vegetation Class

The U.S. National
Vegetation Classification
Tropical, temperate and boreal forests, woodlands and tree savannas characterized by broadly mesomorphic (including scleromorphic) tree growth forms (including broad-leaved, needle-leaved, sclerophyllous, palm, bamboo trees, and tree ferns), typically with at least 10% cover (but tropical tree savannas up to 40% cover, when trees <8 m tall), irregular horizontal spacing of vegetation structure, and spanning humid to seasonally dry tropical to boreal and subalpine climates and wet to dry substrate conditions. Includes native forests, as well as managed, and some plantation forests where human management is infrequent.
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Translated Name:Mesomorphic Tree Vegetation Class
Colloquial Name:Forest & Woodland
Trees with broadly mesomorphic (including scleromorphic) growth forms (including broad-leaved, needle-leaved, sclerophyllous, palm, and bamboo trees, and tree ferns) characterize this type. Vegetation structure typically has irregular horizontal spacing. The mesomorphic tree canopy is typically >10% cover and often exceeds 5 m in height, and often has both a mature (overstory) and regeneration layer, except in tropical upland savanna regions, where trees typically have >40% cover, are >8 m tall, and the vegetation lacks a substantial graminoid layer. Climates range from humid tropical to boreal and subalpine, with fairly moderate moisture and temperature conditions. Substrate moisture conditions vary from dry to wet. Vegetation includes tropical, temperate, and boreal forests and woodlands.
Mesomorphic tree growth forms (broad-leaved, needle-leaved, and sclerophyllous trees, palms, bamboo trees, and tree ferns) have >10% canopy cover, a spontaneous, irregular horizontal canopy spacing, and overtop other growth forms, except in tropical upland regions, where trees typically have >40% cover, are >8 m tall, and the vegetation lacks a substantial graminoid layer.
Vegetation Hierarchy
Name:Database Code:Classification Code:
Class 1 Forest & Woodland C01 1
Subclass 1.B Temperate & Boreal Forest & Woodland S15 1.B
Subclass 1.A Tropical Forest & Woodland S17 1.A
Plantations, ruderal, and native forest and woodland stands are typically placed in this class. Some plantation forests can be placed here rather than in 7. Agricultural & Developed Vegetation Cultural Class (CCL01) despite having a canopy layer that may be very regular (spaced in planted rows), if the tree regeneration, shrub and ground layers develop spontaneously with irregular horizontal spacing, similar to native forests (i.e., regular human intervention does not occur for these layers). However, where plantations have highly regular horizontal structure, with regular human intervention in all layers (e.g., through cutting, spraying, ground-layer mowing), they may better be placed in 7. Agricultural & Developed Vegetation Cultural Class (CCL01).

Similarly, tree-dominated vegetation that has a natural, irregular horizontal spacing in the tree layer, but highly regular shrub or herb layers because of human intervention, should be placed in 7. Agricultural & Developed Vegetation Cultural Class (CCL01). For example, shade coffee, cacao, and other woody agricultural crops grown under native (or exotic) tree species and in which all non-treed strata layers are subject to regular human intervention should be placed in that class.

Included in this class are low-statured trees that overtop other growth forms. These include tree sapling and seedling stands with trees <2 m, where the tree growth form is at least 10% cover and overtops other growth forms. These include subarctic woodlands and coastal dwarf-tree woodlands that are <2 m but are single-stemmed with definite crowns. Conversely, treed bogs and fens, with low stunted trees and conical canopies, and otherwise sharing the moss and dwarf-shrub layers of open bogs and fens, are placed with those types. Where trees share the same strata as grasslands and shrublands (e.g., tallgrass brush prairie of 1-3 m, with trees <2 m), the vegetation is placed in the shrub- and herb-dominated classes.

Tree cover ranges from 10-100%, and is inclusive of what are called forests, woodlands, and tree savannas, at least in the non-tropical regions. The class limit of 10% tree cover (for mesomorphic tree growth forms) follows that of FAO's Global Forest Resources Assessment 2000 (FAO 2001). We exclude stands of trees planted primarily for agricultural production (such as fruit tree or forest plantations) and typically agroforestry, as well as those in developed lands, such as cities and roadsides (they are placed in Class 7, Formation 7.A.2). However, unlike FAO, we do not include what FAO calls "temporarily unstocked areas" (such as clearcuts, burnt areas) unless the tree growth form is actually present at 10% cover--even if in seedling or sapling form--and exceeds the height of other growth forms.

Other classifications may limit forests and woodland to a narrower range of tree cover. For example, forests and woodlands are sometimes defined as 25-100% cover, and distinguished from tree savannas with 10-25% cover which are included under broadly defined grassland and shrubland classes (Driscoll et al. 1984, FGDC 1997, Grossman et al. 1998, Minnesota DNR 2005b). UNESCO (1973) required that tree savannas have a strong herbaceous layer (>50% graminoid cover). Still, a variety of definitions of tree savanna have been published, from the 10-25% cover noted above, to 10-30% cover in Nelson (2005), 10-40% in UNESCO (1973), and 10-50% cover in Curtis (1959). Blue oak, Engelmann oak, and other woodlands in California Mediterranean woodlands are typically between 10 and 60% cover, and California State ecologists place these in Forest & Woodland (Barbour et al. 2007). However, apart from tree savannas, there are many other forest and woodland types and regions where the degree of canopy closure plays less of a role in defining types, for example, forested swamps and bogs, longleaf pine woodlands (Peet 2006), eastern pine barrens, and subarctic woodlands.

Thus, given the variety of situations, we have chosen a more inclusive definition of forest and woodland that encompasses most tree savanna concepts, and rely on lower levels of the hierarchy to make distinctions based on a combination of biogeography, ecology, and floristics. For example, in the context of the eastern Great Plains tallgrass prairie-forest border, it is common to recognize oak savannas, based on open tree cover levels (e.g., 5-30% tree cover in Nelson 2005), as separate from oak woodlands (30-80% cover) and oak forests (80-100% cover). Savannas may be distinguished from forests or woodlands, but these structural distinctions often correspond to lower-level units of the NVC hierarchy (e.g., group, alliance, and association). Still, Dixon et al. (2014) and others suggest that there may be good ecological reasons to treat upland tropical tree savannas, with 10-40% tree cover, trees <8 m tall, and a substantial graminoid layer as part of 2. Shrub & Herb Vegetation Class (C02), and we allow for that option here.
Synonomy: = Forest (FAO 2001) [Approximately equivalent. Xeromorphic scrub woodlands are probably included here, but otherwise the concepts are very similar.]

Related Type Name:

Short Citation:
  • Bailey 1989
  • Barbour et al. 2007a
  • Curtis 1959
  • Dixon et al. 2014
  • Driscoll et al. 1984
  • Faber-Langendoen et al. 2015c
  • FAO 2001
  • FGDC 1997
  • FGDC 2008
  • Grossman et al. 1998
  • Minnesota DNR 2005b
  • Nelson 2005
  • Peet 2006
  • UNESCO 1973
States/Provinces:
Nations:
Range:Climate zones? Bailey (1989) Domains: Dry, Humid Tropical, Humid Temperate Domain, Subarctic Division of Polar Domain, and Mountain Divisions of Dry Domain. Less common in other divisions of Polar or Dry domains.
US Forest Service Ecoregions
Domain Name:
Division Name:
Province Name:
Province Code:   Occurrence Status:
Section Name:
Section Code:     Occurrence Status:
Growth Forms: Stands are dominated by mesomorphic trees, including broad-leaved deciduous (including mostly deciduous, winter-deciduous, facultatively-deciduous), broad-leaved evergreen (including mostly evergreen), needle-leaved (deciduous and evergreen), sclerophyllous trees, palms, bamboo trees, and tree ferns. Tree growth forms generally have a single main stem and more-or-less definite crowns, and may be as low as 2 m (scrub trees) (e.g., tropical cloud elfin forest, mesquite woodland). Where growth forms are not easily defined, woody plants equal to or >5 m at maturity are considered trees (FGDC 2008).

Structure: Typical stands have one or more of the tree growth forms exceeding 5 m in height, and the canopy has irregular horizontal tree stem spacing, with a minimum of 10% canopy cover (8 m in height and minimum of 40% in tropical forests and woodlands, as low as 2 m in subarctic woodlands). A tree regeneration layer is often present, along with various associated growth forms (shrubs, herbs, nonvasculars). Stands of trees where the tree growth form is short (<5 m) in height but overtopping shrub and herb growth forms, may also be placed in this class.
Climate: Climates range from humid tropical to boreal and subalpine, with fairly moderate moisture and temperature conditions. See details under the various forest to woodland subclasses.

Soil/substrate/hydrology: Dry to wet soils, including those found in swamp forests and mangroves.
Moderate
Fire, wind, and insects are most common; other pathogens, e.g., root- and heart-rots may be significant in creating openings in canopy.
Authors:
Hierarchy Revisions Working Group      Version Date: 02Aug2016


References:
  • Bailey, R. G. 1989. Explanatory supplement to ecoregions map of the continents. Environmental Conservation 16:307-309 with separate map at 1:30,000,000. USDA Forest Service, Washington, DC.
  • Barbour, M. G., T. Keeler-Wolf, and A. A. Schoenherr, editors. 2007a. Terrestrial vegetation of California, third edition. University of California Press, Berkeley.
  • Curtis, J. T. 1959. The vegetation of Wisconsin: An ordination of plant communities. Reprinted in 1987. University of Wisconsin Press, Madison. 657 pp.
  • Dixon, A. P., D. Faber-Langendoen, C. Josse, C. J. Loucks, and J. Morrison. 2014. Distribution mapping of world grassland types. Journal of Biogeography 41(11):2002-2019.
  • Driscoll, R. S., D. L. Merkel, D. L. Radloff, D. E. Snyder, and J. S. Hagihara. 1984. An ecological land classification framework for the United States. Miscellaneous Publication No. 1439. USDA Forest Service, Washington, DC. 56 pp.
  • 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.
  • FAO [Food and Agriculture Organization]. 2001. Global Forest Resources Assessment 2--Main Report. FAO Forestry Paper 140. Food and Agriculture Organization of the United Nations, Rome. 482 pp.
  • FGDC [Federal Geographic Data Committee]. 1997. National Vegetation Classification Standard, FGDC-STD-005. Vegetation Subcommittee, Federal Geographic Data Committee, Reston, VA.
  • FGDC [Federal Geographic Data Committee]. 2008. National Vegetation Classification Standard (Version 2.0). FGDC-STD-005-2008. Vegetation Subcommittee, Federal Geographic Data Committee, Reston, VA. 126 pp.
  • Grossman, D. H., D. Faber-Langendoen, A. S. Weakley, M. Anderson, P. Bourgeron, R. Crawford, K. Goodin, S. Landaal, K. Metzler, K. D. Patterson, M. Pyne, M. Reid, and L. Sneddon. 1998. International classification of ecological communities: Terrestrial vegetation of the United States. Volume I. The national vegetation classification system: Development, status, and applications. The Nature Conservancy, Arlington, VA.
  • Minnesota DNR [Minnesota Department of Natural Resources]. 2005b. Field guide to the native plant communities of Minnesota: The Prairie Parkland and Tallgrass Aspen Parklands provinces. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul.
  • Nelson, P. 2005. The terrestrial natural communities of Missouri. Third edition. Missouri Natural Areas Committee, Department of Natural Resources and the Department of Conservation, Jefferson City, MO. 550 pp.
  • Peet, R. K. 2006. Ecological classification of longleaf pine woodlands. Pages 51-93 in: S. Jose, E. J. Jokela, and D. L. Miller, editors. The Longleaf Pine Ecosystem: Ecology, Silviculture, and Restoration. Springer Science Business Media, LLC, New York.
  • UNESCO [United Nations Educational, Scientific and Cultural Organization]. 1973. International classification and mapping of vegetation. Series 6, Ecology and Conservation. United Nations Educational, Scientific, and Cultural Organization. Paris. 93 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:
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About this document
This document contains type descriptions at the Class 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)