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Ecological site F153BY060NC

Wet Loamy Flats and Depressions

Last updated: 4/02/2025
Accessed: 04/09/2025

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General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

MLRA notes

Major Land Resource Area (MLRA): 153B–Tidewater Area

The MLRA notes section provides a brief description of the entire MLRA. This brief description of the entire MLRA is intended to provide some context about the MLRA that this ecological site is within. A more complete description of the MLRA can be found in Ag Handbook 296 (USDA-NRCS, 2022).

This MLRA stretches along the Atlantic coastline from northern Florida to southern Virginia. It features young marine terrace flats, broad flood plains and deltas, tidal marshes and estuaries, barrier sea islands, and a beach ridge system that spans the length of the MLRA. Its broad, shallow valleys with large rivers, tidal marshes, swamps, estuaries, drowned valleys, sea islands, and beaches, are all features of the Late Quaternary (USDA-NRCS, 2017). The Suffolk Scarp is the upper (western) limit of this MLRA and marks the extent of the ocean shoreline before it retreated during the Wisconsin period of glaciation. Fluctuating ocean levels, along with wave and wind activity, continue to rework sand deposits that comprise the ever-changing barrier sea islands and coastline in this MLRA. The marine terraces are younger to the east and are progressively older and higher inland to the west. The youngest marine terraces adjacent to the coast are very low lying and at high risk of inundation by extreme high tides, wind tides, storm surge, and extreme precipitation events. In addition to the risks of inundation, these low-lying terrestrial and freshwater systems are at high risk of salt water intrusion.

The MLRA is characterized by a persistent high water table. The hydraulic gradient across this MLRA is very low. Overall, elevation ranges from sea level to less than 25 feet (0 to 8 meters). Local relief is mainly about 3 feet (1 meter) or less. Most of the surface water in this MLRA is either coming into the MLRA from the piedmont and upper coastal plain, is managed by ditching, or is ponded on the surface. Surface flow channels originating within the MLRA are extremely subtle, typically blackwater, and flow generally channelizes mostly near the shoreline where tidal processes also impact flooding processes.

The dominant soil orders in this MLRA are Alfisols and Entisols. Ultisols and Histosols are important but are of lesser extent. The soils in the area are characterized by restricted drainage, a thermic temperature regime, and an aquic moisture regime. The study of subaqueous soils is of increasing importance along nearshore coastal waters.

The major soil suborders of the MLRA include: 1) Endoaqualfs, which are very deep and loamy to clayey, 2) Endoaquults, which are very deep and loamy to clayey, 3) Haplosaprists, which are extensive in North Carolina and Virginia, in the Great Dismal Swamp, and in broad upland wetlands known as pocosins, 4) Hapludults, which are in the higher areas of somewhat better drainage, 5) Psamments, 6) Sulfaquents, which are extensive throughout the brackish tidal marshes protected by the barrier and sea islands, 7) Sulfiwassents (subaqueous soils), which formed in low- to moderate-energy estuarine deposits, and 8) Umbraquults, which are very deep and loamy to clayey.

MLRA 153B has a lengthy north-south extent, and it runs parallel to the Atlantic coast. The MLRA extends from the northeastern corner of Florida to southern Virginia. Five states are intersected by the MLRA, including North Carolina (42 percent), Virginia (21 percent), South Carolina (20 percent), Georgia (14 percent), and Florida (3 percent). The MLRA extent makes up about 11,152 square miles (28,884 square kilometers).

Because of climatic differences between the northern and southern reaches of the MLRA, vegetative communities vary with latitude. Loblolly pine, red oak, and white oak are dominant in the uplands, and blackgum, sweetgum, pond pine, laurel oak, water tupelo, and bald cypress are dominant on the bottomland. Longleaf pine and slash pine were dominant historically in the southern part of the area. Understory species common to the MLRA include switchcane, inkberry, large gallberry, greenbrier, wax myrtle, and cabbage palm. Herbaceous understory species include little bluestem, and various panicgrasses.

Major wildlife species include alligator, black bear, white-tailed deer, fox, raccoon, opossum, otter, muskrat, rabbit, mink, squirrel, quail, and mourning dove. The red wolf, an endangered species, is being reintroduced in several parts of the MLRA. The nearshore estuaries of the Chesapeake Bay, the Albemarle-Pamlico estuary systems, and Atlantic Ocean provide habitat for diverse populations of terrestrial and aquatic animal species. The subaquatic vegetation in these coastal lagoon areas provides critical habitat and cover for many shellfish and juvenile finfish. The estuaries host numerous migratory waterfowl and wading birds throughout the year and are an integral part of the Atlantic Flyway.

(USDA-NRCS, 2022)

LRU notes

Currently, Ecological Site Descriptions (ESDs) for MLRA 153B cover the full north-south range of the MLRA. However, climate variation across the north-south extent warrants the development of Land Resource Unit (LRU) classifications to support more precise Ecological Site Descriptions.

Classification relationships

MLRA 153B has overlap with two level III EPA ecoregion concepts: 63) the Middle Atlantic Coastal Plain and 75) the Southern Coastal Plain. Under ecoregions 63 and 75 are a number of lower level (IV) concepts, of which several apply to MLRA 153B. These include: 63b) Chesapeake-Pamlico Lowlands and Tidal Marshes, 63c) Swamps and Peatlands, 63d) Virginia Barrier Islands and Coastal Islands, 63f) Delmarva Uplands), 63g) Carolinian Barrier Islands and Coastal Marshes, and 75j) Sea Islands/Coastal Marsh. (U.S. EPA, 2013)

MLRA 153B overlaps a portion of the US Forest Service Outer Coastal Plain Mixed Forest province (232). The MLRA roughly corresponds to the easternmost portions of the Atlantic Coastal Flatwoods (232C) and the southeastern portion of the Northern Atlantic Coastal Flatwoods (232I) sections. In combination with MLRA 153A, these two MLRAs correspond very closely to the full extent of Sections 232C and 232I. (Cleland et al., 2007)

Based on the USGS physiographic classification system, most of MLRA 153B is in the Sea Island section of the Coastal Plain province, in the Atlantic Plain division. The northern quarter is in the Embayed section of the same province and division. The embayed barrier islands extend from the eastern shore of the Chesapeake Bay in Virginia to north of Charleston, South Carolina (Fenneman et al., 1946). The portion in North Carolina is referred to as the Outer Banks. Large bodies of brackish water, such as Pamlico and Albemarle Sounds, are on the inland side of the barrier islands. The sea islands extend from north of Charleston, South Carolina, to Jacksonville, Florida.

The reference community for this particular site is approximately aligned with Wet Pine Flatwoods (Schafale and Weakely, 1990) and Wet Flatwoods (FNAI, 2010).

Ecological site concept

This site is characterized by loamy soils (dominantly Ultisols) on coastal plain flats and depressions of poorly drained and very poorly drained soils with long hydroperiods. Long hydroperiod refers to relatively long periods of soil saturation and/or inundation, especially during the growing season. Depressions may be either open or closed. The soils on this site are hydric. This site is wet but mostly free from flood plain processes. This site is often associated with moist sites that do not meet hydric criteria, and the transition can be exceptionally subtle.

This site supports a variety of vegetation communities including wet flatwoods, nonriverine and bottomland hardwoods. This ecological site includes some locations associated with Carolina bay landforms. Ecological dynamics on this site are largely driven by precipitation, artificial drainage, and fire.

In this MLRA, this site is at risk of inundation associated with tides and extreme precipitation. It is also at risk of saltwater intrusion. In the tidewater area where hydraulic gradients are so low, this site will not likely drain without ditching.

Associated sites

F153BY010NC	Dry Sands Dry sands often comprise a Carolina bay rim adjacent to and higher on the landscape than a wet loamy flats and depressions.
F153BY020NC	Moist Sands Moist sands often comprise a Carolina bay rim adjacent to and higher on the landscape than a wet loamy flats and depressions.
R153BY130NC	Tidal Marsh on Mineral Soil Tidal marsh is often adjacent to and lower on the landscape than wet flats and depressions.
R153BY140NC	Tidal Marsh on Organic Soil Tidal marsh is often adjacent to and lower on the landscape than wet flats and depressions.
F153BY040NC	Moist Loamy Rises and Flats A moist loamy flat is often associated with and difficult to distinguish from a wet loamy flat. Much of the difference between moist and wet sites is driven by variations in subsurface drainage patterns, which are difficult to see at the surface, but these sites can be distinguished by soil moisture.
F153BY045NC	Moist Clay Rises and Flats A moist clayey flat is often associated with and difficult to distinguish from a wet loamy flat. Much of the difference between moist and wet sites is driven by variations in subsurface drainage patterns, which are difficult to see at the surface, but these sites can be distinguished by soil moisture and texture.

Similar sites

F153BY065NC	Wet Clay Flats and Depressions This site occupies similar landforms and is poorly and very poorly drained, but is comprised of clay soils.
F153BY070NC	Wet Spodosol Flats and Depressions This site occupies similar landforms and is poorly and very poorly drained, but is comprised of Spodosols.
F153AY060NC	Wet Loamy Flats and Depressions This site is on very similar landforms but in an adjacent MLRA where the marine terrace surfaces are older, more dissected, and removed from tidal impacts.
F153BY080NC	Wet Organic Soil Flats and Depressions This site occupies similar landforms and is very poorly drained, but is comprised of Histosols (deep organic soils). The wet loamy flats and depressions includes soils with histic epipedons, mineral soils with an organic surface horizon that is significant but not deep enough to classify as a Histosol.
R153BY130NC	Tidal Marsh on Mineral Soil Tidal marshes on mineral soils may sometimes be mapped on the same soils as the soils tied to this ESD, but these communities are described in R153BY130NC, tidal marshes on mineral soil. The frequency of tidal flooding tends to control the dominant life form on the site.

Table 1. Dominant plant species

Tree	(1) Pinus taeda (2) Pinus elliottii
Shrub	(1) Morella cerifera (2) Lyonia lucida
Herbaceous	(1) Aristida beyrichiana (2) Muhlenbergia expansa

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Physiographic features

This ecological site represents flats and depressions of loamy mineral soils (mostly Ultisols) that are mostly isolated from most flood plain processes. Ponding is the most common inundation process on this ecological site. In general, these flat landforms developed by marine deposition, or ancient fluvial reworking and redeposition.

This ecological site includes some locations associated with Carolina bay landforms. Many of the soils mapped on Carolina bay interiors are also mapped on open depressions and marine terrace or interfluve flats which do not have any bay characteristics, so not all locations represented by this ecological site are Carolina bays.

A Carolina bay is a type of closed depression (USDA-NRCS, 2017). Carolina bay depressions are oval or elliptical and have a long-axis orientated northwest to southeast (figure 1). The most recognizable landform of a Carolina bay is the sand rim, which is often well pronounced on the south and east sides of the depression. While highly recognizable, not all Carolina bays have a sand rim. Furthermore, the mere presence of a sand rim is not sufficient to diagnose current local hydrology, which is essential for determining the type of ecosystem. The most diagnostic landform of a Carolina bay is the oval or elliptical depression below the surrounding landscape surface. While the interior depression is typically shallow, it is lower than the general elevational surface of the surrounding flat, not just lower than the rim. The interior of a Carolina bay can vary significantly from flat to slightly concave, mineral soil to organic soil, and open water to raised peatland. (Ross 2003)

Within geologic time, head cutting headwaters (nick points) may intersect a Carolina bay rim, and the depression may eventually become open (figures 1, 2, and 3). As surface waters begin to flow out of a bay, it becomes an open depression, and it is hydrologically different than a closed depression (figure 2). This is especially true where surface waters flow into and through the landform, and the interior experiences flood plain dynamics (figure 3). Open depressions and flood plain systems within a bay rim may be more appropriately referred to as relict Carolina bays. In large relict Carolina bay interiors, flat topography and distance from an outlet can enable portions of the area to function much like a closed depression, so precise classification of hydrology might be challenging in some locations. Figures 1, 2, and 3 depict MLRA 153A, because Carolina bay landforms are more common in MLRA 153A than in 153B, which might be due to tidal impacts in 153B that work to diminish the landform distinctiveness. Nonetheless, Carolina bay landforms have been witnessed even in subaqueous estuarine environments of MLRA 153B (Soil Survey Staff, 2023).

The interiors of some Carolina bays are occupied by lakes, while others are occupied by domed forested peatlands that rarely pond (Ross, 2003). Some bay interiors are dominated by mineral soils that are seasonally saturated, while others support deep muck and are saturated at or near the soil surface for significant portions of the year (Caldwell et al. 2011). Carolina bays are more defined by landform than vegetation. Vegetation communities well suited to a Carolina bay are determined mostly by soil characteristics and hydroperiod. For Carolina bay interiors with multiple different soil types and hydrologic regimes, see also the similar ESDs with descriptions of Carolina bay site types including: Wet Loamy Flats and Depressions (F153AY060NC and F153BY060NC), Wet Clay Flats and Depressions (F153AY065NC and F153BY065NC), Wet Spodosol Flats and Depressions (F153AY070NC and F153BY070NC), and Wet Histosol Flat and Depressions (F153AY080NC and F153BY080NC). At locations where the Carolina bay landform is now open to both inflow and outflow of surface water, you should examine the following ESDs: Flooded Mineral Soil Flood plains and Terraces (F153AY090NC and F153BY090NC), and Flooded Organic Soil Flood plains and Terraces (F153AY100NC and F153BY100NC).

The Carolina bay rim is typically non-hydric and comprised of sandy soils that create a distinct transition to upland conditions at the bay rim. For information about the vegetation communities on Carolina bay rims, see the following associated ecological sites: Dry Sands (F153AY010NC and F153BY010NC) and Moist Sands (F153AY020NC and F153BY020NC).

Table 2 summarizes physiography of the modal soil concepts. Table 3 summarizes physiography of all soils included in this description.

Figure 1. Numerous intact undissected closed depressional Carolina bay landforms in Bladen County, NC of MLRA 153A. The numerous oval and elliptical shaped depressions are all Carolina bay landforms.

Figure 2. Carolina bay landforms that have been dissected sufficiently to deliver surface water outflows in Bladen County, NC of MLRA 153A. This system now functions as an open depression.

Figure 3. A relict Carolina bay landform in Pender County, NC, of MLRA 153A. This depression is dissected by surface water and now classifies as an open riverine depression. This landform does not fit this site concept. It fits a riparian zone landscape concept.

Table 2. Representative physiographic features

Landforms	(1) Coastal plain > Marine terrace (2) Marine terrace > Flat (3) Marine terrace > Depression (4) Carolina Bay
Runoff class	Negligible
Flooding duration	Very brief (4 to 48 hours)
Flooding frequency	None to rare
Ponding duration	Brief (2 to 7 days)
Ponding frequency	None to rare
Elevation	25 ft
Slope	2%
Ponding depth	7 in
Water table depth	12 in
Aspect	Aspect is not a significant factor

Table 3. Representative physiographic features (actual ranges)

Runoff class	Negligible to low
Flooding duration	Brief (2 to 7 days)
Flooding frequency	None to rare
Ponding duration	Long (7 to 30 days)
Ponding frequency	None to frequent
Elevation	25 ft
Slope	2%
Ponding depth	13 in
Water table depth	12 in

Climatic features

The climate of MLRA 153B is generally warm, temperate, and humid with maritime influences along the coast. The maximum precipitation occurs in summer, and the minimum occurs in autumn. Rainfall is usually of moderate intensity. Occasionally, extreme weather events (e.g., northeasters, tropical storms, and hurricanes) produce large amounts of precipitation and destructive winds. Snowfall may occur in the northern end of the area. The average annual temperature is 57 to 70 degrees F (14 to 21 degrees C), increasing to the south. (USDA-NRCS, 2022)

The youngest marine terraces adjacent to the coast are very low lying and at high risk of inundation by extreme high tides, wind tides, storm surge, and extreme precipitation events. Hurricanes and other storms that combine strong winds with extreme precipitation can topple trees and place this entire MLRA at risk of inundation. Furthermore, sea-level rise puts these low-lying terrestrial and freshwater systems at high risk of salt water intrusion and the damaging impacts of salinization.

Table 4. Representative climatic features

Frost-free period (characteristic range)	211-260 days
Freeze-free period (characteristic range)	261-339 days
Precipitation total (characteristic range)	45-48 in
Frost-free period (actual range)	199-272 days
Freeze-free period (actual range)	242-359 days
Precipitation total (actual range)	45-49 in
Frost-free period (average)	236 days
Freeze-free period (average)	300 days
Precipitation total (average)	47 in

Characteristic range

Actual range

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Figure 4. Monthly precipitation range

Characteristic range

Actual range

Bar

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Figure 5. Monthly minimum temperature range

Characteristic range

Actual range

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Figure 6. Monthly maximum temperature range

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Figure 7. Monthly average minimum and maximum temperature

Figure 8. Annual precipitation pattern

Figure 9. Annual average temperature pattern

Climate stations used

(1) ELIZABETH CITY CGAS [USW00013786], Elizabeth City, NC
(2) CHARLESTON CITY [USW00013782], Charleston, SC
(3) BRUNSWICK 23 S [USW00063856], Saint Marys, GA

Influencing water features

This MLRA is dominated by a persistent high water table, and, on this site, the water table is near the surface during a portion of the growing season for a period sufficiently long to produce anaerobic conditions, thus favoring hydrophytic vegetation. This ecological site is mostly isolated from flood plain processes, so water inputs are mostly precipitation and ground water. This site is at risk of exposure to storm surge and tidal inundation across the MLRA under extreme conditions.

Wetland description

These soils are hydric, but, in order to classify as a wetland, a location must meet soils, hydrology, and vegetation criteria. This site is seasonally saturated and/or ponded, and it is not typically flooded. Some of these sites are sufficiently inland and are not exposed to tidal influences, so they would be palustrine in nature. Those locations exposed to tidal influences classify as estuarine. Most locations associated with frequent tidal influences are likely best described by a different ESD, either R153BY130NC, tidal marsh on mineral soil, or R153BY140NC, tidal marsh on organic soil.

Soil features

The soils of this site are all primarily loamy in texture, and most are Ultisols formed in deep marine and fluviomarine mineral deposits. They are acidic and deep, but some soils on this site have the potential to form a root restricting layer due to repeated wetting and drying cycles. They are hydric meaning that they are saturated near the surface during a portion of the growing season for a period sufficiently long to produce anaerobic conditions. This site represents those locations where soils meet hydric criteria, but this site is often associated with moist sites that do not meet hydric criteria, and the transition can be exceptionally subtle. The soils on this site are poorly and very poorly drained. This site includes soils with a shallow organic surface horizon (i.e., histic epipedons). In this MLRA, these soils are at risk of salt water intrusion.

Soil series on this site include: Arapahoe, Ballahack, Conaby, Daleville, Deloss, Ellabelle, Fallsington, Gullrock, Hobcaw, Icaria, Lumbee, Myatt, Nakina, Newholland, Nimmo, Ogeechee, Pantego, Pasquotank, Plummer, Portsmouth, Rains, Tomotley, Wasda, Weeksville, Weston, Williman, Woodington, and Yonges.

Arapahoe, Nimmo, Portsmouth, and Tomotley are modal. These soils are at least moderately deep.

Table 5. Representative soil features

Parent material	(1) Marine deposits (2) Fluviomarine deposits
Surface texture	(1) Fine sandy loam (2) Loam (3) Sandy loam (4) Muck
Drainage class	Very poorly drained to poorly drained
Permeability class	Moderately rapid to rapid
Depth to restrictive layer	Not specified
Soil depth	80 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	4.4 – 6.9 in
Soil reaction (1:1 water) (0-10in)	3.5 – 6
Subsurface fragment volume <=3" (0-40in)	4%
Subsurface fragment volume >3" (0-40in)	Not specified

Table 6. Representative soil features (actual values)

Drainage class	Very poorly drained to poorly drained
Permeability class	Moderately rapid to rapid
Depth to restrictive layer	20 in
Soil depth	64 – 80 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	2.6 – 8.2 in
Soil reaction (1:1 water) (0-10in)	3.5 – 6.5
Subsurface fragment volume <=3" (0-40in)	35%
Subsurface fragment volume >3" (0-40in)	Not specified

Ecological dynamics

The most dominant ecological drivers on this site are hydrology, fire, tides, and extreme weather. Although it is regulated today, artificial drainage has been extensively applied to manage this site. Once applied, the effects of drainage are persistent. Historically, the use of fire by indigenous civilizations may have also been extensive. Some limited wildfire and prescribed fire occur today, but fire suppression has been the norm since the 20th century. Both fire and drainage can impact the thickness of organic surface soil accumulation. Persistent and prolonged saturation slows decomposition and allows for the accumulation of organic surface soil material. Hurricanes produce winds and rain that can have significant impact. Saturated soils decrease the rooting strength of trees and make them more susceptible to windfall. Extreme precipitation can increase and prolong inundation and saturation.

The variety of vegetation communities that occur on this site are representative of a variety of strategies to adapt to fire return intervals. For example, longleaf pine flatwoods are well adapted to periodic low intensity surface fires on short return intervals, whereas bottomland hardwoods are well suited to thrive only in the prolonged absence of fire. Pond pine woodlands are maintained by intense stand replacement fire. In this ESD, longleaf pine dominated wet flatwoods are the reference community, because they represent the dominant precolonial forest community. It is probable that wet longleaf pine flatwoods were a cultural state maintained by indigenous civilizations, and, in most locations, they no longer dominate the landscape. (Peet and Allard, 1993)

Hurricanes produce winds and rain that can have significant impact. Wet soils decrease the rooting strength of trees and make them more susceptible to windfall. Extreme precipitation can increase and prolong inundation and saturation. The lack of hydrologic gradient between these sites and sea level can further increase and prolong inundation and saturation following an extreme precipitation event.

In this MLRA, intrusion of salt water into the soil profile can have significant impacts on vegetation. Low lying areas are at particularly high risk of salinization. Extensive ditching across this MLRA increases exposure of the landscape to salinization. As sea level rises, a dense salt-water wedge moves further inland up these ditches exposing more of the landscape to these processes.

In the State and Transition Model below for this site where soils meet hydric criteria, hydrologically driven transitions represent both changes in conditions across space as well as changes in conditions over time. Ideally, transitions would represent only changes over time. As updates to the soil survey allow, individual states within this site may be split into individual distinct sites.

If following the soil survey has brought you to this ESD, but you find yourself in a graminoid marsh community, please refer to the ESD titled Tidal Marsh on Mineral Soil, R153BY130NC. Some of the same soils mapped on this ecological site are also mapped on marsh locations, but the complexity of salinity and tidal dynamics make it necessary to describe the marsh systems in a separate ESD.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Wet Pine Flatwoods

2. Nonriverine Swamp Woodlands

3. Drained

4. Restored

5. Salinized

States 1, 5 and 2 (additional transitions)

1. Wet Pine Flatwoods

5. Salinized

2. Nonriverine Swamp Woodlands

T1A	-	Historical anthropogenic replacement of Longleaf pine
T1C	-	Drainage
T1D	-	Salinization
T2A	-	Re-establishment of Longleaf pine
T2C	-	Drainage
T2D	-	Salinization
T3A	-	Restoration of hydrology, vegetation, and fire
T3B	-	Salinization
T4A	-	Salinization

State 1 submodel, plant communities

1.1. Wet Longleaf Pine Savanna

1.2. Shrubby Wet Flatwoods

1.1.2	-	Decreasing fire return interval
1.2.1	-	Increasing fire return interval

State 2 submodel, plant communities

2.1. Pond Pine Woodland

2.2. Bay Woodland (Baygall)

2.3. Nonriverine Bottomland Hardwoods

2.4. Cypress - Gum - Tupelo Swamp

2.1.2	-	Loss of periodic fire
2.1.3	-	Decreased acidity and loss of periodic fire
2.1.4	-	Loss of periodic fire and increased inundation
2.2.1	-	Periodic fire
2.2.3	-	Decreased acidity
2.2.4	-	Increased inundation
2.3.1	-	Increased acidity and periodic fire
2.3.2	-	Increased acidity
2.3.4	-	Increased inundation
2.4.1	-	Decreased inundation and periodic fire
2.4.2	-	Decreased inundation and undisturbed succession
2.4.3	-	Decreased inundation

State 3 submodel, plant communities

3.1. Drained Forest

3.2. Cultivated Agriculture

3.3. Managed Grassland

3.4. Urban Development

3.1.2	-	Land clearing and cultivation
3.1.3	-	Land clearing and establishment of grassland
3.1.4	-	Land clearing and urban development
3.2.1	-	Establishment of trees
3.2.3	-	Establishment of grassland
3.2.4	-	Urban development
3.3.1	-	Establishment of trees
3.3.2	-	Establishment of cultivation
3.3.4	-	Urban development

State 4 submodel, plant communities

4.1. Restored Wet Loamy Flats and Depressions with Brief Hydroperiods

4.2. Restored Wet Loamy Flats and Depressions with Moderate Hydroperiods

4.3. Restored Wet Loamy Flats and Depressions with Long Hydroperiods

4.1.2	-	Increased periods of saturation
4.1.3	-	Increased periods of saturation
4.2.1	-	Decreased periods of saturation
4.2.3	-	Increased periods of saturation
4.3.1	-	Decreased periods of saturation
4.3.2	-	Decreased periods of saturation

State 5 submodel, plant communities

5.1. Salinized Forest

5.2. Salinized Cropland

State 1
Wet Pine Flatwoods

Wet pine flatwoods often occur on the landscape as an ecotone between wet Histosol flats and depressions and moist flats and depressions. The distinction between wet loamy flats and depressions from moist flats and depressions can be exceptionally subtle with many sites supporting an even mix of facultative wetland, facultative, and facultative upland species. This reference state presents as two relatively distinct community phases: a pine savanna community and a shrubby flatwoods community. The relationship between the two community phases seems poorly understood. The relationship between the two community phases will tend to reflect slight changes in fire return intervals and lengths in hydroperiod. Nonetheless, across the MLRA it is consistently understood that the pine savanna community occurs where fire intervals are more frequent (every 1-3 years), and the shrubby flatwoods are more common where fire is less frequent (every 5-10 years). Extreme fluctuations in these drivers may warrant a state change with changes in dynamic soil properties, shifting Wet Pine Flatwoods to Pond Pine Woodlands. (FNAI, 2010; Peet and Allard, 1993; Schafale et al., 1990)

Community 1.1
Wet Longleaf Pine Savanna

The wet longleaf pine savanna community is characterized by a moderate to sparse overstory pine cover with sparse to absent woody midstory or understory and a dense groundcover of graminoids and other herbs. A low shrub cover is often present. (FNAI, 2010; Peet and Allard, 1993; Schafale et al., 1990)

Resilience management. The wet longleaf pine savanna community persists at locations where low intensity ground fires occur nearly every 1 to 3 years.

Dominant plant species

longleaf pine (Pinus palustris), tree
wax myrtle (Morella cerifera), shrub
inkberry (Ilex glabra), shrub
saw palmetto (Serenoa repens), shrub
pineland threeawn (Aristida stricta), grass
Beyrich threeawn (Aristida beyrichiana), grass
cutover muhly (Muhlenbergia expansa), grass
toothache grass (Ctenium aromaticum), grass

Community 1.2
Shrubby Wet Flatwoods

The shrubby wet flatwoods community is characterized by a moderate to sparse overstory pine cover with a dense shrubby understory. Shrubby wet flatwoods may also support a woody midstory, while graminoid ground cover tends to be sparse to absent. (FNAI, 2010; Peet and Allard, 1993; Schafale et al., 1990)

Resilience management. The shrubby wet flatwoods persist where fire return intervals are longer or where cool season fires predominate. Fire return intervals on the order of 5 to 7 years or 5 to 10 years are believed to support the shrubby wet flatwoods community.

Dominant plant species

longleaf pine (Pinus palustris), tree
pond pine (Pinus serotina), tree
sweetbay (Magnolia virginiana), tree
swamp bay (Persea palustris), tree
wax myrtle (Morella cerifera), shrub
fetterbush lyonia (Lyonia lucida), shrub
saw palmetto (Serenoa repens), shrub
pineland threeawn (Aristida stricta), grass
Beyrich threeawn (Aristida beyrichiana), grass

Pathway 1.1.2
Community 1.1 to 1.2

Fire return interval decreasing from 1 to 3 years to roughly 5 to 10 years.

Pathway 1.2.1
Community 1.2 to 1.1

Fire return interval increasing from roughly 5 to 10 years to approximately 1 to 3 years.

State 2
Nonriverine Swamp Woodlands

Community 2.1
Pond Pine Woodland

Pond pine woodlands tend to occur on the outer perimeter of a raised bog or domed pocosin. Pond pine woodlands persist well and increasingly dominate this site type in the presence of periodic fire. Bay woodlands and pond pine woodlands are believed to be hydrologically very similar with fire dynamics driving the difference. Pond pine withstands low intensity fire well as it sprouts from epicormic buds. The serotinous cones of pond pine also enable it to reoccupy a site quickly after catastrophic fire. (FNAI, 2010; Nelson, 1986; Schafale et al., 1990; Sharitz et al., 1982)

Dominant plant species

pond pine (Pinus serotina), tree
loblolly bay (Gordonia lasianthus), tree
sweetbay (Magnolia virginiana), tree
red maple (Acer rubrum), tree
swamp bay (Persea palustris), tree
swamp titi (Cyrilla racemiflora), shrub
fetterbush lyonia (Lyonia lucida), shrub
maleberry (Lyonia ligustrina), shrub
large gallberry (Ilex coriacea), shrub
inkberry (Ilex glabra), shrub
coastal sweetpepperbush (Clethra alnifolia), shrub
laurel greenbrier (Smilax laurifolia), shrub
wax myrtle (Morella cerifera), shrub
giant cane (Arundinaria gigantea), grass
Virginia chainfern (Woodwardia virginica), other herbaceous
sphagnum (Sphagnum), other herbaceous

Community 2.2
Bay Woodland (Baygall)

Bay woodland communities tend to occur on the outer perimeter of a raised bog or domed pocosin. Bay woodlands persist well and increasingly dominate this site type in the long term absence of fire. Bay woodlands and pond pine woodlands are believed to be hydrologically very similar with fire dynamics driving the difference. Bay species sprout after low-intensity surface fire, but increasing bay abundance will increase fire intensity. Fires can be expected to be intense in the dense vegetation of a bay woodland, and bay trees do not typically survive high intensity fire. (FNAI, 2010; Nelson, 1986; Schafale et al., 1990; Sharitz et al., 1982)

Dominant plant species

loblolly bay (Gordonia lasianthus), tree
sweetbay (Magnolia virginiana), tree
swamp bay (Persea palustris), tree
red maple (Acer rubrum), tree
fetterbush lyonia (Lyonia lucida), shrub
large gallberry (Ilex coriacea), shrub
swamp titi (Cyrilla racemiflora), shrub
wax myrtle (Morella cerifera), shrub
coastal doghobble (Leucothoe axillaris), shrub
swamp doghobble (Eubotrys racemosus), shrub
dahoon (Ilex cassine), shrub
Virginia sweetspire (Itea virginica), shrub
laurel greenbrier (Smilax laurifolia), shrub
coral greenbrier (Smilax walteri), shrub
sphagnum (Sphagnum), other herbaceous

Community 2.3
Nonriverine Bottomland Hardwoods

Nonriverine bottomland hardwoods are primarily deciduous closed canopy forests with very little understory herbaceous layer development. They tend to occur on locations with relatively higher pH (less acidic) and in depressions intermediate between uplands and swamps that are more permanently saturated. They seem unlikely to carry fire, even when surrounding woodlands are burned. They may represent a stable climax community. (FNAI, 2010; Schafale et al., 1990)

Dominant plant species

sweetgum (Liquidambar styraciflua), tree
laurel oak (Quercus laurifolia), tree
swamp chestnut oak (Quercus michauxii), tree
American elm (Ulmus americana), tree
red maple (Acer rubrum), tree
swamp tupelo (Nyssa biflora), tree
American hornbeam (Carpinus caroliniana), shrub
dwarf palmetto (Sabal minor), shrub
swamp bay (Persea palustris), shrub
wax myrtle (Morella cerifera), shrub
highbush blueberry (Vaccinium corymbosum), shrub
American holly (Ilex opaca), shrub
sedge (Carex), grass

State 2.4
Cypress - Gum - Tupelo Swamp

A nonriverine Cypress - Gum - Tupelo swamp is typically a basin wetland vegetated with hydrophytic trees and shrubs that can withstand an extended hydroperiod. These swamps are highly variable in size, shape, and species composition. Historically, these sites were once more strongly dominated by large trees, particularly bald cypress. Small stands of large virgin cypress in nonriverine swamp environments still persist today, but logging has reduced most stands to relatively small sized gum and red maple trees, often with dense shrubs. Depending on the hydrology and fire history, shrubs may be found throughout a basin swamp or they may be concentrated around the perimeter. Historically, fires were probably rare, but might have occurred in drought periods. Areas susceptible to more frequent fire probably supported shrub bog communities rather than swamp. It seems likely that most Nonriverine Swamp Forests occur primarily in environments which have more nutrient influx than bogs or are more permanently wet and are protected from fire. (FNAI, 2010; Nelson, 1986; Schafale et al., 1990)

Dominant plant species

bald cypress (Taxodium distichum), tree
pond cypress (Taxodium ascendens), tree
swamp tupelo (Nyssa biflora), tree
water tupelo (Nyssa aquatica), tree
red maple (Acer rubrum), tree
laurel oak (Quercus laurifolia), tree
water oak (Quercus nigra), tree
sweetbay (Magnolia virginiana), shrub
swamp bay (Persea palustris), shrub
swamp titi (Cyrilla racemiflora), shrub
fetterbush lyonia (Lyonia lucida), shrub
coastal sweetpepperbush (Clethra alnifolia), shrub
dahoon (Ilex cassine), shrub
wax myrtle (Morella cerifera), shrub
common buttonbush (Cephalanthus occidentalis), shrub
laurel greenbrier (Smilax laurifolia), shrub
coral greenbrier (Smilax walteri), shrub
maidencane (Panicum hemitomon), grass
chainfern (Woodwardia), other herbaceous
sphagnum (Sphagnum), other herbaceous
arrowhead (Sagittaria), other herbaceous
lizard's tail (Saururus cernuus), other herbaceous
smallspike false nettle (Boehmeria cylindrica), other herbaceous
beaksedge (Rhynchospora), other herbaceous
bladderwort (Utricularia), other herbaceous
royal fern (Osmunda regalis), other herbaceous
Walter's sedge (Carex striata), other herbaceous

Pathway 2.1.2
Community 2.1 to 2.2

Fire suppression

Pathway 2.1.3
Community 2.1 to 2.3

Decreased acidity and loss of periodic fire

Pathway 2.1.4
Community 2.1 to 2.4

Fire suppression and increased inundation

Pathway 2.2.1
Community 2.2 to 2.1

Periodic fire

Pathway 2.2.3
Community 2.2 to 2.3

Decreased acidity

Pathway 2.2.4
Community 2.2 to 2.4

Increased inundation

Pathway 2.3.1
Community 2.3 to 2.1

Increased acidity and periodic fire

Pathway 2.3.2
Community 2.3 to 2.2

Increased acidity

Pathway 2.3.4
Community 2.3 to 2.4

Increased inundation

Pathway 2.4.1
Community 2.4 to 2.1

Periodic fire and decreased inundation from some natural change to local hydrology.

Pathway 2.4.2
Community 2.4 to 2.2

Decreased inundation and undisturbed succession. Decreased inundation from some natural change to local hydrology.

Pathway 2.4.3
Community 2.4 to 2.3

Decreased inundation

State 3
Drained

This is a relatively wet site within a landscape with a persistent and nearly ubiquitous shallow water table across the MLRA. Historically, these sites have been drained frequently to support a variety of land uses including forestry, agriculture, and development. This drained state is included in this STM because this state exists widely today across the landscape. Drainage of wetlands today is significantly regulated. NRCS is required to consider impacts to wetlands according to Federal laws including, but not limited to, the Clean Water Act, the Wetland Conservation provisions of the Food Security Act of 1985, and State, Tribal, and local laws. It is the policy of NRCS to protect and promote wetland functions and values in all NRCS assistance (National Environmental Compliance Handbook (NECH) 610.36).

Community 3.1
Drained Forest

Forests are typically drained to facilitate timber production, especially artificial regeneration. The timber industry in the Southeast has artificially expanded the ecological footprint of slash pine and loblolly pine in particular.

Community 3.2
Cultivated Agriculture

Drainage is typically necessary on this site in order to successfully maintain cultivated agriculture.

Community 3.3
Managed Grassland

Lands drained in order to support pasture and/or hayland management.

Community 3.4
Urban Development

Lands developed to urban land use conditions.

Pathway 3.1.2
Community 3.1 to 3.2

Land clearing and cultivation

Pathway 3.1.3
Community 3.1 to 3.3

Land clearing and establishment of grassland

Pathway 3.1.4
Community 3.1 to 3.4

Land clearing and urban development

Pathway 3.2.1
Community 3.2 to 3.1

Establishment of trees. The timber industry in the Southeast has artificially expanded the ecological footprint of slash pine and loblolly pine in particular, mostly through significant site preparation during stand establishment.

Pathway 3.2.3
Community 3.2 to 3.3

Establishment of grassland

Pathway 3.2.4
Community 3.2 to 3.4

Urban development

Pathway 3.3.1
Community 3.3 to 3.1

Establishment of trees

Pathway 3.3.2
Community 3.3 to 3.2

Establishment of cultivation

Pathway 3.3.4
Community 3.3 to 3.4

Urban development

State 4
Restored

After land on this site has been drained, it is impossible to return fully to reference conditions that existed at that location prior to drainage, especially at locations that remained under active drainage management for long periods of time. Restoration efforts might include blocking and removing drainage structures, revegetation, and reintroduction of periodic fire.

Community 4.1
Restored Wet Loamy Flats and Depressions with Brief Hydroperiods

This community represents restored wet loamy flats and depressions that experience brief hydroperiods. The soils are saturated and inundated for short periods. The longest saturation event within 30cm of the soil surface during the growing season ranges from 14 – 50 days. Sites that have been restored for at least 20 years have facultative, and wetland obligate vegetation that dominate the community. The restored plant community composition is driven both by a species' ability to thrive in these conditions as well as whether or not it was planted at the restoration sites that were studied. (Moritz, 2021)

Dominant plant species

bald cypress (Taxodium distichum), tree
loblolly pine (Pinus taeda), tree
pond cypress (Taxodium ascendens), tree
red maple (Acer rubrum), tree

Community 4.2
Restored Wet Loamy Flats and Depressions with Moderate Hydroperiods

This community represents restored wet loamy flats and depressions that experience moderate hydroperiods. The soils are saturated and inundated for much of the growing season. The longest saturation event within 30cm of the soil surface during the growing season ranges from 51 – 100 days. Prolonged periods of saturation and reduction reduces microbial decomposition rates, which allows for more organic carbon to accumulate in the soils when compared to restored wet loamy flats and depressions that experience brief hydroperiods. Sites that have been restored for at least 20 years have facultative, facultative wet, and wetland obligate vegetation that dominate the community. The restored plant community composition is driven both by a species' ability to thrive in these conditions as well as whether or not it was planted at the restoration sites that were studied. (Moritz, 2021)

Dominant plant species

bald cypress (Taxodium distichum), tree
pond cypress (Taxodium ascendens), tree
pond pine (Pinus serotina), tree
red maple (Acer rubrum), tree
willow oak (Quercus phellos), tree

Community 4.3
Restored Wet Loamy Flats and Depressions with Long Hydroperiods

This community represents restored wet loamy flats and depressions that experience long hydroperiods. The soils are saturated and inundated for much of the year. The longest saturation event within 30cm of the soil surface during the growing season ranges from 101 days to the entire growing season. Prolonged periods of saturation and reduction reduces microbial decomposition rates, which allows for more organic carbon to accumulate in the soils when compared to restored wet loamy flats and depressions that experience moderate hydroperiods. Sites that have been restored for at least 20 years have facultative wet, and wetland obligate vegetation that dominate the community. The restored plant community composition is driven both by a species' ability to thrive in these conditions as well as whether or not it was planted at the restoration sites that were studied. (Moritz, 2021)

Dominant plant species

bald cypress (Taxodium distichum), tree
overcup oak (Quercus lyrata), tree
pond cypress (Taxodium ascendens), tree
pond pine (Pinus serotina), tree

Pathway 4.1.2
Community 4.1 to 4.2

Increased periods of saturation. The longest saturation event within 30cm of the soil surface during the growing season ranges from 51 days to 100 days.

Pathway 4.1.3
Community 4.1 to 4.3

Increased periods of saturation. The longest saturation event within 30cm of the soil surface during the growing season ranges from 101 days to the entire growing season.

Pathway 4.2.1
Community 4.2 to 4.1

Decreased periods of saturation. The longest saturation event within 30cm of the soil surface during the growing season ranges from 14 days to 50 days.

Pathway 4.2.3
Community 4.2 to 4.3

Increased periods of saturation. The longest saturation event within 30cm of the soil surface during the growing season ranges from 101 days to the entire growing season.

Pathway 4.3.1
Community 4.3 to 4.1

Decreased periods of saturation. The longest saturation event within 30cm of the soil surface during the growing season ranges from 14 days to 50 days.

Pathway 4.3.2
Community 4.3 to 4.2

Decreased periods of saturation. The longest saturation event within 30cm of the soil surface during the growing season ranges from 51 days to 100 days.

State 5
Salinized

Any community on this site that has become salinized by the impacts of salt water inundation or intrusion. Saltwater intrusion is the movement of saltwater into freshwater systems. The process occurs mostly by lateral flow into areas adjacent to coastal waters or ditch systems that connect saltwater bodies. These ditch systems are designed to drain freshwater off of a site, but sea level rise and extreme tidal events push saltwater up these ditch systems and expose more of the landscape to salinization processes. Salinization can also occur as storm surge and/or extreme high tides push saltwater flooding and inundation over the top of these terrestrial freshwater systems.

Community 5.1
Salinized Forest

The nature of a salinized forest depends on the level and persistence of salts in the soils. Forest vegetation impacts range from stunted vegetation to forests of standing dead trees. Standing dead forests are often an indication that the dominant vegetation is shifting to a marsh community.

Community 5.2
Salinized Cropland

Soil salinization converts once verdant farm fields to dead, bare soil areas.

Transition T1A
State 1 to 2

A variety of industrial exploitations cycles, loss of periodic fire cycles, and industrial removal of longleaf pine.

Transition T1C
State 1 to 3

The drained state is included in this STM because this state exists widely today across the landscape. This transition is included to show how we got to where we are today. Drainage of wetlands today is significantly regulated. NRCS is required to consider impacts to wetlands according to Federal laws including, but not limited to, the Clean Water Act, the Wetland Conservation provisions of the Food Security Act of 1985, and State, Tribal, and local laws. It is the policy of NRCS to protect and promote wetland functions and values in all NRCS assistance (National Environmental Compliance Handbook (NECH) 610.36).

Transition T1D
State 1 to 5

Sea level rise, tidal inundation, and soil saltwater intrusion.

Transition T2A
State 2 to 1

Renewed planting of longleaf pine as well as expanded application of low-intensity, frequent prescribed fire

Transition T2C
State 2 to 3

Transition T2D
State 2 to 5

Sea level rise, tidal inundation, and soil saltwater intrusion.

Transition T3A
State 3 to 4

Remove, plug, or otherwise restore drainage, revegetate, and reintroduce periodic fire.

Transition T3B
State 3 to 5

Sea level rise, tidal inundation, and soil saltwater intrusion.

Transition T4A
State 4 to 5

Sea level rise, tidal inundation, and soil saltwater intrusion.

Additional community tables

Supporting information

Inventory data references

Data collection and analysis of field data will be performed during the Verification Stage of ESD development.

Other references

Ash, A., E. McDonald, E. Kane, and C. Pories. 1983. Natural and modified pocosins: Literature synthesis and management options. U.S. Fish and Wildlife Services, Dept. Biol., Tech. Rep. FWS/OBS-83/04. U.S. Fish and Wildlife Services, Washington, D.C.

Caldwell, P., M. Vepraskas, J.D. Gregory, R.W. Skaggs, and R.L. Huffman. 2011. Linking Plant Ecology and Long-Term Hydrology to Improve Wetland Restoration Success. Transactions of the ASABE. 54: 2129-2137. DOI: 10.13031/2013.40662

Cleland, D.T., J.A. Freeouf, J.E. Keys, G.J. Nowacki, C.A. Carpenter, W.H. McNab. 2007. Ecological Subregions: Sections and Subsections for the conterminous United States. General Technical Report WO-76D. U.S. Department of Agriculture, Forest Service. Washington, D.C.

Dimick, B. P., J. Stucky, W. Wall, M. Vepraskas, T. Wentworth, and C. Arellana. 2010. Plant‐soil‐ hydrology relationships in three Carolina bays in Bladen County, North Carolina, USA. Castanea 75(4): 407‐420

Fenneman, N.M., and D.W. Johnson. 1946. Physical divisions of the United States. U.S. Geological Survey, Physiographic Committee. Scale 1:700,000.

Florida Chapter, Soil and Water Conservation Society. 1989. 26 Ecological Communities of Florida. 147 pp.

Florida Natural Areas Inventory (FNAI). 2010. Guide to the natural communities of Florida: 2010 edition. Florida Natural Areas Inventory, Tallahassee, FL.

McNab, W.H.; D.T. Cleland, J.A Freeouf, J.E. Keys Jr., G.J. Nowacki, C.A. Carpenter, comps. 2007. Description of ecological subregions: sections of the conterminous United States [CD-ROM]. Gen. Tech. Report WO-76B. Washington, DC: U.S. Department of Agriculture, Forest Service. 80 pp.

Moritz, C. 2021. Evaluating mitigation sites in Carolina bay wetlands that were previously converted to agriculture. Institutional Repository at North Carolina State University, North Carolina State University, Raleigh, NC, 1–323.

Moritz C., M. Vepraskas, and M. Ricker. 2022. Hydrology and Vegetation Relationships in a Carolina Bay Wetland 15 Years after Restoration. Wetlands. 42. DOI: 10.1007/s13157-022-01530-0.

Nelson, J.B. 1986. The Natural Communities of South Carolina Initial Classification and Description, South Carolina Wildlife and Marine Resources Department, Division of Wildlife and Freshwater Fisheries.

Peet, R.K., and D.J. Allard. 1993. Longleaf Pine Vegetation of the Southern Atlantic and Eastern Gulf Coast Regions: A Preliminary Classification. In Proceedings of the Tall Timbers Fire Ecology Conference, No. 18, The Longleaf Pine Ecosystem: ecology, restoration and management, edited by Sharon M. Hermann, Tall Timbers Research Station, Tallahassee, FL, 1993.

Ross, T.E. 2003. Pocosins and Carolina Bays Compared, The North Carolina Geographer, Volume 11: 22-32

Schafale, M.P., and A.S. Weakley. 1990. Classification of the Natural Communities of North Carolina Third Approximation. North Carolina Natural Heritage Program. 321 pp.

Sharitz R.R., and J.W. Gibbons. 1982. The ecology of southeastern shrub bogs (pocosins) and Carolina bays: a community profile. U.S. Fish and Wildlife Service, Division of Biological Services, Washington, D.C. FWS/OBS-82/04. 93 pp.

Soil Survey Staff. 2023. Web Soil Survey. USDA Natural Resources Conservation Service. http://websoilsurvey.sc.egov.usda.gov/ (accessed 16 February 2023).

U.S. Department of Agriculture, Natural Resources Conservation Service. 2017. Geomorphic Description System, Version 5.0. Schoeneberger, P.J., and D.A. (eds). USDA-NRCS, National Soil Survey Center, Lincoln, NE.

U.S. Department of Agriculture, Natural Resources Conservation Service. 2022. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. Agriculture Handbook 296.

U.S. Environmental Protection Agency. 2013. Level III and IV ecoregions of the continental United States: Corvallis, Oregon, U.S. EPA, National Health and Environmental Effects Research Laboratory, map scale 1:3,000,000, https://www.epa.gov/eco-research/level-iii-and-iv-ecoregions-continental-united-states.

Contributors

Matthew D. Duvall
Christopher Moritz

Approval

Charles Stemmans, 4/02/2025

Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Author(s)/participant(s)
Contact for lead author
Date	04/02/2025
Approved by	Charles Stemmans
Approval date
Composition (Indicators 10 and 12) based on	Annual Production