Natural Vegetation Classification System of Arkansas

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Hierarchy is explained in text (Foti et al. 1994).


(I)=indicator species

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Terrestrial

1. Forest (61-100% tree cover; trees > 5m tall)

1.A. Mainly evergreen forest (>75% evergreen)

1.A.9. Temperate evergreen needle-leaved forest

1.A.9.b. Temperate evergreen needle-leaved forest with rounded crowns

I. 1.a. Pinus echinata, Probably even-aged, resulting from disturbance, NW and Coastal Plain.
II. 2.a. Pinus taeda, Probably even-aged, resulting from disturbance, Primarily SE.
III. 3.a. Pinus echinata - Pinus taeda - Carya spp, Dry-mesic to dry sites, principally Coastal Plain.
1.A.9.c. Temperate evergreen needle-leaved upland forest with conical crowns
I. 1.a. Juniperus virginiana, Often high pH sites, sometimes rock, unburned.
1.B. Mainly deciduous or mixed forest (25%-75% evergreen)

1.B.2. Cold-deciduous forest, with evergreen broad-leaved trees and climbers (25%-75% evergreen)

1.B.2.a. Cold-deciduous forest with evergreen broad-leaved trees and climbers

I. 1.a. Fagus grandifolia - Ilex opaca (I), In Coastal Plain on sandy branch bottoms.
1.B.2.b. Cold-deciduous broad-leaved upland forest with evergreen needle-leaved trees
I. Quercus spp.(stellata, marilandica) - Pinus echinata - Carya spp.
1.a. Pinus echinata - Quercus stellata - Carya texana, Mesic to dry sites, NW and Coastal Plain.
1.b. Pinus echinata - Quercus stellata - Juniperus virginiana, Dry, open sites resulting from disturbance, NW and Coastal Plain.
1.c. Quercus stellata - Pinus echinata - Quercus marilandica (I), Dry or very dry sites, mostly NW and Coastal Plain.
1.d. Quercus stellata - Quercus marilandica - Juniperus virginiana, like 2a., but out of range of pines; higher pH.
II. Quercus spp.(alba,rubra) - Pinus echinata - Carya spp.
2.a. Quercus rubra - Pinus echinata - Quercus stellata, Dry sites, principally NW.
2.b. Quercus rubra - Pinus echinata - Carya texana, Dry sites, principally NW.
2.c. Pinus echinata - Quercus rubra - Quercus velutina, Mesic to xeric sites, NW.
2.d. Pinus echinata - Quercus rubra - Carya tomentosa, Dry to xeric sites, NW.

3.a. Quercus alba - Quercus rubra - Pinus echinata, Dry-mesic to dry sites, principally west half.
3.b. Quercus alba - Pinus echinata - Quercus (velutina,falcata) Dry-mesic to dry sites, principally west half.
3.c. Pinus echinata - Quercus alba - Carya tomentosa, Mesic to dry sites, NW and Coastal Plain.
III. Pinus taeda - Pinus echinata - Quercus spp.
4.a. Pinus taeda - Pinus echinata - Quercus spp. (stellata,alba, falcata), Dry to dry-mesic sites, principally Coastal Plain, probably deserves more detailed classification, but few natural stands remain.
4.b. Pinus taeda - Quercus stellata - Quercus falcata, Mesic to dry sites, principally Coastal Plain. Moister sites than 4.
5.a. Pinus taeda - Quercus (phellos, nigra,stellata), On occasionally flooded to dry sites, usually Coastal Plain.
6.a. Pinus taeda - Liquidambar styraciflua, Successional on old fields.
IV. Juniperus virginiana
7.a. Juniperus virginiana - Quercus muehlenbergii - Fraxinus quadrangulata, High pH sites or out of range of pine.
7.b. Juniperus virginiana - Rhus spp. - Diospyros, Old fields.
7.c. Juniperus virginiana - Quercus alba - Quercus velutina
1.B.3. Cold-deciduous forest without evergreen needle-leaved trees

1.B.3.a. Temperate lowland and submontane broad-leaved cold-deciduous forest

I. Fagus grandifolia
1.a. Fagus grandifolia - Magnolia tripetala (I), Principally northwest on mesic sites.
1.b. Fagus grandifolia - Acer saccharum - Quercus spp. (alba, muehlenbergii, rubra), Mixed mesic forest (see David Graney, RNA nomination, Dismal Hollow), primarily Ozarks. Tilia americana may also occur, Acer is seldom in the community with Fagus.
1.c. Fagus grandifolia - Acer spp. (rubrum, saccharum) - Liriodendron tulipifera (I), Mixed mesophytic forest, Crowley's Ridge.
II. Quercus alba - mixed hardwoods
2.a. Liriodendron tulipifera - Quercus alba, On Crowley's Ridge, typically dry sites.
3.a. Acer saccharum - Quercus spp. (alba,rubra) - Carya spp. (ovata,tomentosa,cordiformis), Most common community for A. saccharum in Arkansas. Ozarks, Coastal Plain.
4.a. Quercus alba - Carya spp. (ovata,tomentosa), Dry-mesic to mesic sites throughout state on uplands.
4.b. Quercus alba - Liquidambar styraciflua - Carya tomentosa, Mesic to dry-mesic sites throughout state on uplands.
4.c. Quercus alba - Quercus velutina - Quercus falcata, Mesic to dry-mesic communities throughout state on uplands, Quercus velutina most characteristic of southern Ozarks; Liquidambar styraciflua is common.
5.a. Quercus alba - Quercus stellata, Dry to dry-mesic sites in uplands throughout state.
5.b. Quercus phellos - Quercus alba - Quercus falcata var. pagodifolia, Moist uplands, Arkansas River Valley, also with Liquidambar styraciflua.
III. Quercus rubra - Quercus spp.
6.a. Quercus rubra - Quercus alba - Nyssa sylvatica, Mesic, north-facing slopes, richer sites than 6.b.
6.b. Quercus rubra - Quercus alba - Quercus velutina,mesic north-facing slopes, often includes Q. stellata and Carya texana.
IV. Quercus falcata - Quercus spp.
7.a. Quercus shumardii - Quercus falcata, Dry-mesic sites, particularly in southwestern Arkansas, Ouachitas and Coastal Plain. Sometimes bottomlands.
7.b. Quercus falcata - Quercus alba - Quercus velutina, Dry to dry-mesic sites; perhaps same community as 4c, but probably drier sites, more northerly distribution than 7.a.
V. Quercus stellata
8.a. Quercus stellata - Quercus marilandica,- (Quercus rubra) Dry to xeric sites, northwest. Quercus rubra appears to have bimodal distribution: mesic and xeric.
8.b. Quercus stellata - Quercus (alba,velutina) - Carya texana, Dry sites, mostly northwest.
VI. 9.a. Liquidambar styraciflua, Old fields.
1.B.3.b. Montane cold-deciduous forest
I 1.a. Quercus alba (stunted), Forest at high elevations in Ouachitas. Ice and wind are key physical factors. May have full canopy cover, but trees are less than 15 feet tall.
2. Woodland (26%-60% cover; trees over 5m tall)

2.A. Mainly evergreen woodland

2.A.2 Evergreen needle-leaved woodland

2.A.2.b. Evergreen needle-leaved woodland with conical crowns

I. Juniperus virginiana - Quercus spp.
1.a. Juniperus virginiana - Quercus muehlenbergii, Throughout state, primarily on high pH, thin soils, unburned.
1.b. Juniperus virginiana - Quercus stellata, Throughout state, primarily on high pH, thin soils, unburned.
1.c. Juniperus virginiana - Quercus stellata - Fraxinus quadrangulata, Throughout state, primarily on high pH, thin soils, unburned, mostly dolomite.
2.a. Juniperus virginiana - Liquidambar styraciflua, Old fields.
2.B. Mainly deciduous or mixed woodland (25%-75% evergreen)

2.B.3. Cold-deciduous woodland with evergreen needle-leaved trees

2.B.3.a. Mixed upland woodland, evergreens with rounded crowns

I. Pinus echinata - Quercus spp.
1.a. Pinus echinata - Quercus stellata - Quercus marilandica (I), Xeric sites in northwest, Coastal Plain. Q. marilandica often var. ashei = Quercus X bushii.
1.b. Pinus echinata - Quercus alba - Quercus falcata, NW, Coastal Plain, Fire maintained.
2.a. Pinus echinata - Quercus incana - Quercus arkansana, Sandhills of Coastal Plain.
II. Juniperus ashei - Quercus spp.
3.a. Juniperus ashei, Ozarks (dolomite outcrops) and Coastal Plain (chalk).
3.b. Juniperus ashei - Quercus sinuata (=durandii), Coastal Plain (White Cliffs, Little River County) on chalk.
3.c. Juniperus ashei - Quercus muehlenbergii - Fraxinus quadrangulata, Dolomite outcrops in Ozarks.
2.B.4. Cold-deciduous woodland (<25% evergreen)

2.B.4.a. Cold-deciduous upland deciduous woodland

I. Quercus spp. - Carya texana
1.a. Quercus alba - Quercus stellata, Xeric sites in northwest, occasionally elsewhere.
1.b. Quercus stellata - Quercus marilandica - Carya texana, Xeric sites in northwest, occasionally elsewhere. Sometimes stunted. Q. marilandica often var. ashei = Quercus X bushii.
2.a. Quercus arkansana - Quercus incana, Sandhills of Coastal Plain.
4. Shrubland (shrubs <5m >25% cover; trees >5m <10% cover)

4.A. Mainly evergreen shrubland

4.A.2.a. Evergreen needle-leaved shrubland

I.Juniperus spp. - Quercus spp.
1.a. Juniperus virginiana - Quercus muehlenbergii - Fraxinus quadrangulata, Rock outcrops of northwest.
1.b. Juniperus ashei - Quercus muehlenbergii - Fraxinus quadrangulata, Rock outcrops of northwest.
4.B.3.a. Temperate deciduous shrubland
I. 1.a. Quercus alba - Quercus stellata, In northwest, often at high elevation in Ouachitas.
II. Mixed shrub species
2.a. Vaccinium spp. (arboreum, stamineum, pallidum), Usually on thin soils or rock outcrops, glades in northwest.
2.b. Crataegus spp. (marshallii, crus-galli), Thicket.
5. Herbaceous

5.A. Tall Grassland

5.A.1 Tall Grassland consisting mainly of sod grasses

5.A.1.a. Tall dense upland grassland

I. Mesic Prairie
1.a. Tripsacum dactyloides, In moist to wet areas of prairies throughout state.
1.b. Panicum virgatum, In moist areas of prairies throughout state, particularly Grand Prairie of MAP.
1.c. Andropogon gerardii - Sorghastrum avenaceum, Mesic areas of prairies throughout state.
1.d. Andropogon virginicus, Old fields.
5.B. Medium tall grassland

5.B.1. Medium tall grassland consisting mainly of sod grasses

5.B.1.a. Medium tall upland dense grassland

I. Dry Prairie
1.a. Schizachyrium scoparium - In dry areas of prairies.
1.b. Sporobolus asper - Especially in Ozarks.
1.c. Bouteloua curtipendula - On very dry, thin soils.
5.C. Grasslands with a tree layer

5.C.1. Tall Grasslands with a tree layer

5.C.1.a. Evergreen needle-leaved tree layer

I. Schizachyrium - Andropogon - Pinus
1.a. Schizachyrium scoparium - Pinus echinata - Quercus stellata, NW, fire and thin soils, savanna/barrens, glades. Andropogon gerdardii common.
1.b. Andropogon virginicus - Juniperus virginiana, Old fields.
5.C.1.b. Mainly deciduous or mixed tree layer
I. 1.a. Schizachyrium scoparium - Quercus spp. (stellata,shumardii, muehlenbergii), Oak savanna on thin soils, burned.
II. Dry Shrubby Grassland
1.a. Bouteloua curtipendula - Quercus stellata - Juniperus virginiana, On thin soils and rock outcrops in northwest and Coastal Plain.
1.b. Schizachyrium scoparium - Ilex decidua - Fraxinus pennsylvanica, Blackland prairies of Coastal Plain.
1.c. Andropogon virginicus - Sassafras albidum, Old fields.
5.C.3. Short grassland with a tree layer

5.C.3.b. Deciduous tree layer

I. 1.a. Aristida spp. - Quercus stellata, On saline soils.
6. Barren/sparsely vegetated

6.A.1.b. Sparsely vegetated

I. Sparsely vegatated
1.a. Bare rock, In northwest and Coastal Plain, glades.
1.b. Lichen covered rock, In NW, glades.
1.c. Talus, In northwest, particularly Ouachitas.
1.d. Chasmophytic vegetation (Juniperus spp. on rock), In northwest and Coastal Plain, glades.
2.a. Eroding slopes, Throughout the state, particularly along streams.
2.b. Bare Soil.
II. Fern - Moss
3.a. Nonvascular plants - Fern (moist) or Moss (dry).
3.b. Shaded cliff (mosses, fern), In NW and Coastal Plain.
Palustrine

(These are distinguished at lower levels in the national classifications; that change can be made, but if so it will be harder to find the wetland communities.)

1.B.3.c. Cold deciduous alluvial forest

I. Quercus lyrata
1.a. Quercus lyrata - Carya aquatica, In bottomlands flooded less than 50% (ca. 20%-40%). Throughout except Ozarks and Crowley's Ridge.
1.b. Quercus lyrata - Carya aquatica - Fraxinus spp., In bottomlands flooded less than 50% (ca. 20%-40%), Throughout except Ozarks, and Crowley's Ridge.
1.c. Quercus lyrata - Carya aquatica - Quercus nuttallii (=texana), In bottomlands flooded less than 50% (ca. 20%-40%), Throughout the state except Ozarks, and Crowley's Ridge.
2.a. Quercus lyrata - Quercus phellos, Poorly drained bottomlands subject to long-duration flooding, Primarily Coastal Plain, MAP.
2.b. Quercus lyrata - Quercus phellos - Carya ovata, Poorly drained bottomlands subject to long-duration flooding, Primarily Coastal Plain, MAP.
2.c. Quercus lyrata - Quercus phellos - Quercus nuttallii (=texana), Poorly drained bottomlands subject to long-duration flooding, Primarily Coastal Plain, MAP.
2.d. Quercus lyrata - Quercus phellos - Liquidambar styraciflua, Poorly drained bottomlands subject to long-duration flooding, Primarily Coastal Plain, MAP.
2.e. Quercus lyrata - Quercus phellos - Quercus nigra,
3.a. Quercus lyrata - Celtis laevigata - Carya aquatica, Primarily MAP.
3.b. Quercus lyrata - Celtis laevigata - Fraxinus pennsylvanica, Primarily MAP.
3.c. Quercus lyrata - Gleditsia aquatica - Celtis laevigata, Primarily MAP.
II. Carya aquatica
5.a. Carya aquatica, Primarily MAP.
5.b. Carya aquatica - Fraxinus pennsylvanica - Quercus lyrata, Primarily MAP.
III. Quercus falcata var. pagodifolia
6.a. Quercus falcata var. pagodifolia - Quercus phellos - Liquidambar styraciflua, In bottomlands not subject to long duration flooding often includes Q. nigra.
6.b. Quercus falcata var. pagodifolia - Quercus alba - Quercus nigra, In bottomlands not subject to long duration flooding.
6.c. Quercus falcata var. pagodifolia - Quercus michauxii - Quercus phellos, In bottomlands not subject to long duration flooding.
7.a. Quercus falcata var. pagodifolia - Quercus nuttallii (=texana), In bottomlands subject to moderate duration flooding.
IV. Celtis laevigata
8.a. Celtis laevigata - Carya aquatica, In poorly drained bottomlands, MAP.
8.b. Celtis laevigata - Fraxinus pennsylvanica - Carya illinoensis, Generally sandy, poorly drained bottomlands.
9.a. Celtis laevigata - Fraxinus pennsylvanica - Ulmus americana, In poorly drained bottomlands, MAP and often includes Q. phellos.
9.b. Celtis laevigata - Ulmus crassifolia - Fraxinus spp., In poorly drained bottomlands, MAP and often includes Q. phellos.
V. Quercus nuttallii (=texana)
10.a.Quercus nuttallii (=texana) - Quercus lyrata - Quercus phellos, In bottomlands subject to medium to long duration flooding, mostly southeast.
10.b.Quercus nuttallii (=texana) - Quercus lyrata - Liquidambar styraciflua, In bottomlands subject to medium to long duration flooding, mostly southeast.
10.c.Quercus nuttallii (=texana) - Quercus lyrata - Carya aquatica, In bottomlands subject to medium to long duration flooding, mostly southeast.
10.d.Quercus nuttallii (=texana) - Quercus lyrata - Fraxinus spp., In bottomlands subject to medium to long duration flooding, mostly southeast.
11.a.Quercus nuttallii (=texana) - Celtis laevigata - Fraxinus pennsylvanica.
11.b.Quercus nuttallii (=texana) - Celtis laevigata - Ulmus spp.
VI. Quercus palustris
12.a.Quercus palustris - Quercus lyrata - Carya laciniosa,often includes Carya ovata.
12.b.Quercus palustris - Fraxinus pennsylvanica - Quercus phellos, often includes Carya ovata.
12.c.Quercus palustris - Quercus phellos - Quercus lyrata.
12.d.Quercus palustris - Quercus phellos - Liquidambar styraciflua.
VII. Quercus phellos
13.a.Quercus phellos.
14.a.Quercus phellos - Quercus palustris - Carya aquatica.
14.b.Quercus phellos - Quercus palustris - Quercus lyrata.
14.c.Quercus phellos - Quercus laurifolia.
15.a.Quercus phellos - Quercus lyrata,often includes Carya ovata.
16.a.Quercus phellos - Quercus nigra,often includes Q. pagoda,Q. alba.
VIII. Liquidambar styraciflua
1.B.3.d. Cold-deciduous swamp forest
I. Taxodium distichum - mixed hardwood
1.a. Taxodium distichum, In long-duration swamps, throughout except Ozarks and Crowley's Ridge.
1.b. Taxodium distichum - Nyssa aquatica, In long-duration swamps, throughout except Ozarks and Crowley's Ridge.
2.a. Taxodium distichum - Quercus lyrata, In bottomlands flooded ca. 50% of the year throughout state.
2.b. Taxodium distichum - Quercus lyrata - Fraxinus spp.
II. Nyssa
3.a. Nyssa aquatica.
3.b. Nyssa aquatica - Taxodium distichum - (sometimes includes Nyssa biflora).
4.a. Magnolia virginiana - Nyssa (aquatica,sylvatica), Seeps and occasionally streamsides in Coastal Plain.
4.B.3.c. Deciduous alluvial shrubland
I. Cornus amomum
1.a. Cornus amomum, Stream floodplains, northwest.
II. Mixed shrub
2.a. Planera aquatica, Bottomlands subject to long-term inundation, mostly southeast.
3.a. Forestiera acuminata, Bottomlands subject to moderate to long-term inundation, mostly southeast.
4.a. Cephalanthus occidentalis, On areas subject to long-term inundation throughout the state.
5.A.4.a. Tall grass
I. Tall grass
1.a. Tripsacum dactyloides, Moist prairies.
2.a. Panicum virgatum, Moist to wet prairies.
5.A.4.b. Tall grass consisting mainly of bunch grasses
I. Tall grass
1.a. Schizachyrium scoparium - Panicum virgatum, Wet sites, occasionally flooded, usually in prairies throughout.
II. Typha - Zizaniopsis Marsh
2.a. Typha latifolia, Open areas subject to long-term inundation, throughout.
3.a. Zizaniopsis milinacea, South, swamps and marshes.
III. 4.a. Arundinaria gigantea, Common understory, becomes dominant when overstory is removed, e.g., by fire or cutting.
5.B.2.c. Medium tall vegetation with deciduous shrub layer
I. Fen
1.a. Parnassia grandifolia - Carex lurida, Fen - high pH ground water seepage.
II. Sedge - rush
2.a. Scirpus spp. - Juncus spp.
3.a. Carex spp. - Osmunda spp. - Sphagnum spp., Acid seeps.
Riverine
1.B.3.c. Forest
I. Salix - Populus
1.a. Acer negundo - Carya illinoensis - Populus deltoides, Also Acer rubrum, Platanus occidentalis. Riverfronts.
2.a. Populus deltoides, Riverfronts, usually sandy, throughout the state.
2.b. Populus deltoides - Quercus lyrata - Quercus nuttallii, Riverfronts, usually sandy, throughout the state.
2.c. Populus deltoides - Salix nigra - Celtis laevigata, Riverfronts, usually sandy, throughout the state.
3.a. Salix nigra, In poorly drained riverfronts.
II. Betula - Platanus - Acer Riverfront
4.a. Betula nigra - Platanus occidentalis, On well-drained riverfronts, primarily NW.
5.a. Acer saccharinum - Ulmus americana, In infrequently flooded bottomlands, primarily northwest.
4.B.3.c. Shrub
I. Shrub willow
1.a. Salix caroliniana, Gravel, sand bars in northwest.
2.a. Salix exigua, Gravel, sand bars, ditchbanks, throughout the state.
5.A.1.c. Herbaceous with woody layer broad-leaved deciduous
I. 1.a. Xanthium strumarium - Cynodon dactylon (alien) - Populus deltoides, Sandbars.
6. Barren/Sparsely vegetated

6.A.1.a. Bare

I. Bare
1.a. Sand bar
1.b. Gravel bar
2.a. Mud flat
3.a. Eroding bank
Lacustrine
1.B.3.d. Forest
I. 1.a. Taxodium distichum - Nyssa aquatica, Shallow lakes and margins of others, mostly southeast.
4.B.3.c. Shrub
I. 1.a. Cephalanthus occidentalis, Shallow lakes and margins of others, mostly southeast.
5.D.2.a. Herbaceous
I. Marsh
1.a. Nuphar lutea, Shallow to medium depth lakes, mostly southeast.
2.a. Typha latifolia, Open shallow edges, throughout.
3.a. Scirpus spp. - Juncus spp., Open shallow edges, throughout.
6. Barren/Sparsely Vegetated 6.A.1.a. Bare
I. 1.a. Mud flat

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