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The association's physiognomy, which is the structure or outward appearance as expressed by the dominant growth forms.

Physiognomy types and their definitions
Forest: vegetation dominated by tree species (> 5 m tall), the crowns of which generally form a continuous canopy with typically > 30% cover (by CNVC convention).

Woodland: vegetation dominated by tree species (> 5 m tall), the crowns of which form a sparse, discontinuous canopy as a result of ecological limitations such as climate, shallow soils, wetlands, etc; woodland canopies are typically between 10% and 30% cover (by CNVC convention).

Shrubland: vegetation dominated by shrub species, > 10 cm tall.

Grassland: vegetation consisting primarily of grass species, typically occurring on sites that are arid or at least well drained.

Forb Meadow: vegetation dominated by forb species, often occurring on moist sites. A forb is a non-graminoid herb with relatively broad leaves and/or showy flowers, including monocots and dicots.

Dwarf Shrubland: vegetation dominated by shrub species < or = 10 cm tall.

Cryptogamic Vegetation: vegetation dominated by cryptogamic species, typically bryophytes and lichens. A cryptogam is a plant that reproduces by means other than the production of seeds (e.g., spore-producing bryophytes and pteridophytes).

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Association name

The scientific name is the formal name of the Association and is listed first, followed by the English and French common names.

Species within a vegetation stratum are separated by a dash ( - ).  Species of different vegetation strata are separated by a slash ( / ). When a species name appears in parentheses, it indicates that the species is important, but not always present.

See Nomenclature Conventions for CNVC Units for a more detailed explanation of how the CNVC develops names for its units.

An Association is a vegetation classification unit defined on the basis of a characteristic range of species composition, diagnostic species occurrence, habitat conditions, and physiognomy. For more information see the Glossary.

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Subassociations, CNVC Alliance and CNVC Group

Subassociations: represent species occurrences or dominance patterns that do not indicate ecological differences strong enough to warrant recognition at the Association rank.

CNVC Alliance: an aggregation of Associations, with consistency in dominant and/or diagnostic species, describing regionally repeating vegetation patterns at the local to sub-regional scale. Alliances are created by grouping Associations that are ecologically “related” into more generalized ecological units (e.g., successionally related forest Associations on similar edaphic conditions can be aggregated into more generalized Alliances).

CNVC Group: for upland vegetation that includes zonal vegetation: an aggregation of Alliances within the regional vegetation defined by a Macrogroup, with consistency in dominant and/or diagnostic species. Groups describe regionally generalized  vegetation pattterns attributable to ecological drivers such as edaphic or geological conditions within the Macrogroup.

for azonal vegetation: see EcoVeg interpretive guidelines, Table 4.


For more information, see the Glossary or The CNVC Hierarchy.


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A conceptual description of the Association (i.e., "essence" of the type as conceived by the concept authors / peer review panel). It includes synoptic statements about characteristic features of vegetation using both common and scientific names, environment, dynamics and range. It includes reference to generalized age, seral stage, abundance, and patch size where these are relevant details. It may include a brief comparison to similar CNVC associations if doing so helps to clarify the understanding of the Association (longer comparisons are included in the "Comments" section). If there are subassociations, there is a brief reference to them and their distinctions.

For interim factsheets (i.e., "Short" factsheets), the Concept and Range sections may be the only components of the Type Description provided. As additional resources are available, full factsheets are published.

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A description of the vegetation characteristics of the Association, including common, dominant and diagnostic species, typical community structure and physiognomy, seral stage, patch size etc. In "Short" factsheets, the "Vegetation" section may not be completed, however, this information may be presented briefly in the "Concept" section.

Vegetation cover classes derived from the stratum covers on the Vegetation Summary page are used to describe the average vegetation abundance within each layer. Cover class definitions are provided in the table below.

Layer Descriptive Terms Used Vegetation
Cover Class
Tree sparse   <= 25%
open   26-40%
moderately closed   41-60%
closed   > 60%
Shrub and
Herb /
Dwarf Shrub
poorly / lightly developed layer;
sparse; low abundance
  <= 20%
moderately developed layer;
moderate abundance
well-developed layer;
high abundance
dense layer; dense   > 60%
Moss and
lightly or poorly developed
  <= 30%
moderately developed   31-50%
well-developed   51-80%
continuous   > 80%


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A description of the habitat and ecological process relationships characteristic of the Association (e.g., typical climatic, soil / site, or disturbance drivers). In "Short" factsheets, the "Environment" section may not be completed, however, this information may be presented briefly in the "Concept" section.

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A summary of the seral stage (e.g., young early seral) and known disturbance conditions (e.g., fire, wind, flooding, biotic agent) that influence the development, temporal stability and within-stand structural and physiognomic patterns of the Association. When possible, an interpretive assessment of the successional relationships between the Association and other vegetation conditions (especially CNVC associations) is included. In "Short" factsheets, the "Dynamics" section may not be completed, however, this information may be presented briefly in the "Concept" section.

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A synoptic description of the geographic range of the Association. The areas that are represented by plot data, as well as the known or projected range extension beyond the plot coverage, are described. The locations of plots with known coordinates for the Association are illustrated on a map of Canada on the "Distribution" page of the factsheet.

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Conservation Status (NatureServe)

.Global (range-wide), National and Subnational (provincial / territorial / state) conservation status of the Association according to NatureServe's standard international protocol. The national ranks are not yet available for Canada.

The conservation status of an association is designated by a number from 1 to 5, preceded by a letter reflecting the appropriate geographic scale of the assessment (G = Global, N = National, and S = Subnational). The numbers have the following meaning:
1 = critically imperiled
2 = imperiled
3 = vulnerable
4 = apparently secure
5 = secure.
If the conservation status of a CNVC association has not yet been ranked at a particular geographic scale, then "NR" (Not Ranked) is used in place of a number. If the CNVC Association is not equivalent to any provincial / territorial / state or international community types that have been ranked by NatureServe, then "no applicable rank" is used.

For more information, see:

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A typical stand- or landscape-level photograph of the Association.

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Edatopic Grid

The edatopic grid is a qualitative representation of relative soil moisture and soil nutrient regimes. See Page 4 of Understanding the Factsheet for definitions of the classes on the grid axes. The green rectangle is an estimate of the edatopic range typically occupied by the Association, inferred from site, soil and/or vegetation observations in plot data and confirmed by expert opinion.

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Association number

A unique identifier for the Association.

For an explanation of CNVC identifier codes, see Nomenclature Conventions for CNVC Units.