Ecological dynamics
Historically, this ecological site was part of a vast forested landscape with processes and functions directly connected to the highly dynamic nature of the Mississippi River (Gardiner and Oliver, 2005). Widespread changes to the natural flow of the river coupled with conversion of the landscape to alternative uses challenges the notion of ascribing reference conditions for this site (see Stanturf et al., 2001). Determination of these conditions are still under review, but they are assumed to consist of mature forest stands with little human-induced modifications to local hydrologic regimes (e.g., ditching or water control structures); intensive landuse histories (e.g., over a century of row-cropping); repeated, heavy indiscriminate timber harvests (e.g., high-grading); or high incidence of exotic species. In theory, such sites would support multiple age classes of woody vegetation and structural complexity of the forest profile (statements deduced from the metrics provided in Meadows and Nowacki, 1996). These characteristics subsumes the concept of “functionality” of the system. Although the full description of reference conditions is currently incomplete, a considerable compilation of observations and forest research over the past century have provided invaluable information on species presence, suitability, and productivity of important forest resources on this site. Their presence, management, and sustainability form the basis of the “perceived” reference state for the site.
Although the soil series are essentially the same (i.e., Alligator and Sharkey soils), the greater relief of this site corresponds to better drainage compared to the adjoining backswamp flats (Putnam and Bull, 1932). Higher runoff rates on these low ridges likely contribute to a greater diversity of natural vegetation. Putnam and McKnight (1949) mentioned that sweetgum and water oaks (i.e., willow oak, Nuttall oak, and water oak) predominate on the clayey ridges of the Delta National Forest in Mississippi, but they also emphasized that several other species are associates. In an early description of forest cover types in the Mississippi River Delta Region, Putnam and Bull (1932) placed their “red gum” and “red gum – clay land oaks” cover types as “very common” associations on low clay ridges. These general cover types, today, are primarily included within the sweetgum – willow oak type (Type 92) by the Society of American Foresters (see Eyre, 1980). A variant of the latter is the cedar elm – water oak – willow oak type, which was described as occurring “…on poorly drained impervious soils on low, indistinct or flattened first-bottom ridges” (statement first appeared in Putnam, 1951 and included in Eyre, 1980). A more commonly used name for this cover type is the sweetgum – red oaks association (see Hodges, 1997 and Meadows and Stanturf, 1997). Principal species of these types include sweetgum, Nuttall oak, willow oak, and water oak with associates of American elm, green ash, sugarberry, red maple, cedar elm, red mulberry, persimmon, and honey locust. In the wetter areas, overcup oak, water hickory, and Drummond's maple are components.
Another prominent and common forest type of this site is the elm – ash – sugarberry association (corresponds to Type 93, the sugarberry – American elm – green ash type in Eyre, 1980). Putnam (1951) treated the type as being a temporary association that commonly occurred after heavy cutting and/or fire. Similarly, Putnam and Bull (1932) described their oaks – elm – ash and hackberry – elm types as a “residual type” following heavy cutting of the “red gum – clay land oaks” association. However, Hodges (1997) emphasized that most successional pathways on poorly drained sites in major bottoms tend toward the elm – ash – sugarberry association, and that pathway also includes the potential fate of the sweetgum – red oaks type. The principal species of the elm – ash – sugarberry association are prolific seed producers and are shade tolerant when young. These biological attributes apparently give them a competitive edge over their oak associates, which are shade intolerant, have poor seedling establishment under high shade, and have slow early growth (Eyre, 1980). The elm – ash – sugarberry type is capable of self-replacement and can persist for 200 to 300 years. Still, there are potential natural events and management scenarios that may favor development of the sweetgum – red oaks community. These factors ultimately depend on the occurrence and level of disturbance (e.g., a catastrophic stand replacing event) and the presence of advance regeneration within the stand prior to disturbance. Under the disturbance scenario, the presence of advance regeneration of oaks may favor establishment of the red oak – sweetgum association following a stand replacing event. Although, in the absence of large-scale disturbances, the long-term trend favors the development and persistence of the shade tolerant, elm – ash – sugarberry association (Hodges, 1997; Stanturf et al., 2001).
Overall, forest cover on this site is minor compared to other uses. Most areas have been cleared and are used for row crop production and some areas have been land leveled with soil surface cuts of up to 3 feet to meet irrigation needs. The principal crops are soybeans, cotton, wheat, and rice on the lesser sloping areas or in areas that have been precision land formed. Secondary uses include pasturage and hay production. Wetness limitations on this site have led to the installation of drainage systems in many areas.
Following this narrative, a “provisional” state and transition model is provided that includes the “perceived” reference state and several alternative (or altered) vegetation states that have been observed and/or projected for this ecological site. This model is based on limited inventories, literature, expert knowledge, and interpretations. Plant communities may differ from one location to the next depending on the severity of local land use activities and rates of deposition. Depending on objectives, the reference plant community may not necessarily be the management goal.
The environmental and biological characteristics of this site are complex and dynamic. As such, the following diagram suggests pathways that the vegetation on this site might take, given that the modal concepts of climate and soils are met within an area of interest. Specific locations with unique soils and disturbance histories may have alternate pathways that are not represented in the model. This information is intended to show the possibilities within a given set of circumstances and represents the initial steps toward developing a defensible description and model. The model and associated information are subject to change as knowledge increases and new information is garnered. This is an iterative process. Most importantly, local and/or state professional guidance should always be sought before pursuing a treatment scenario.
State 1
Reference: Backswamp Ridge Forest
Removal of the pre-settlement natural communities began long before thorough studies and investigations were initiated. Modifications to the natural hydrodynamics and drainage patterns coupled with location-specific land use histories have further complicated species-site relationships. Such complexity will likely be reflected in much variability in vegetation composition and structure of local forest stands (Stanturf et al., 2001). Accordingly, reference conditions for this site are currently under review. They are perceived to consist of mature forest stands that support a diverse mix of southern bottomland hardwoods adapted to the poorly drained clayey soils and geomorphic setting of low ridges and rises within backswamp environments. Once assigned, the reference community will not represent the pre-settlement forest community, but it should identify an assemblage of naturally occurring species that reflects and contributes to regional biodiversity and local forest ecology. Implicated in the latter is that the “local” geomorphic features and drainage patterns of this soil-site environment should not have been drastically altered or removed (e.g., land leveled or extensively ditched and drained).
Based on former forest surveys and available literature, the sweetgum – willow oak (or red oaks) association is provisionally selected to represent reference conditions based on its perceived commonality or dominance on this site (see Putnam and Bull, 1932). A second forest type reported on this site is the sugarberry – American elm – green ash association or a variant of the type. It is important to note that many of the same species are shared among the two types (Putnam, 1951; Eyre, 1980) with differences mainly occurring in the concentration and abundance of shade intolerant versus shade tolerant components (Eyre, 1980). The widespread occurrence of the sugarberry – American elm – green ash community is often attributed to former land use practices that removed commercially valuable trees, typically sweetgum and oaks, while leaving behind species of little commercial value (Putnam and Bull, 1932). Based on the preceding coupled with the propensity of the type to replace other plant communities due to shade tolerance (see Clatterbuck and Meadows, 1993; Allen et al., 2001; Oliver et al., 2005), the sugarberry – American elm – green ash type was not considered to be the representative community of this ecological site. This position will be critically reviewed and evaluated during the next phase of ecological site development, the verification stage.
The return or transition pathway from the altered states (currently, only States 2 and 3) back to reference conditions is intended to represent the suite of hardwood species that, reportedly, frequently to occasionally occur and are favored in management on this site. Realistically, it may not always be possible to return to a “perceived” reference state from a former altered condition. While planting and establishing trees appropriate for a site may be possible, achieving restoration of the understory and other system functions are challenges that may never be realized (Stanturf et al., 2001; Flinn and Vellend, 2005).
Community 1.1
Sweetgum – Red Oaks Bottomland Hardwoods
The sweetgum – red oaks cover type is tentatively recognized as the reference community phase for the site. Other names that appear to closely apply to this type include red gum and red gum – clay land oaks (Putnam and Bull, 1932); sweetgum – water oaks (Putnam, 1951); and sweetgum – willow oak (Eyre, 1980). This community phase represents the composition, successional stage, and structural complexity of forest stands supporting perceived reference conditions. Exemplary examples are likely to be restricted to areas that have had few detrimental impacts to local drainage patterns or intensive land use histories. Such conditions are likely to be very rare, today and may only occur locally (e.g., public natural areas).
Principal species of the perceived reference community include sweetgum, Nuttall oak, willow oak, and water oak with chief associates of American elm, green ash, and sugarberry. In northern portions of the site, pin oak (Quercus palustris) and hackberry (Celtis occidentalis) may be important components. Minor associates of the type include common persimmon, cedar elm, eastern cottonwood (Populus deltoides), red maple, and honeylocust. Overcup oak, water hickory, Drummond's maple, and rarely, baldcypress (Taxodium distichum) may become associates on wetter locations. Cherrybark oak (Q. pagoda) and American sycamore (Platanus occidentalis) occasionally occur on better drained locations. The understory and undergrowth may consist of sugarberry, green ash, oaks, maple, red mulberry, possumhaw, greenbrier (Smilax spp.), American buckwheat vine (Brunnichia ovata), peppervine (Nekemias arborea), trumpet creeper (Campsis radicans), and eastern poison ivy (Toxicodendron radicans) (Eyre, 1980). Ground cover may consist of blackberry (Rubus spp.), sedges (Carex spp.), smallspike false nettle (Boehmeria cylindrica), Virginia dayflower (Commelina virginica), and rosette grass (Dichanthelium spp.) (Devall and Ramp, 1992). Notable variations in species abundance and dominance often occur from one location to the next (Putnam and Bull, 1932; Putnam, 1951). Plausible sources of variations may be due to former disturbance histories, local soil-site differences, or stand development trajectories. One recognized cover-type variant is the cedar elm – water oak – willow oak association (Eyre, 1980) where cedar elm is a dominant component of the community.
Broadfoot (1976) provided productivity estimates of several important tree species that naturally occur and are “favored in management” on this site. The following are site index values from Broadfoot and, according to the author, they were generated from dominant and codominant trees in well-stocked, even-aged stands that had no modifying influence or manipulated treatments (e.g., no evidence of burning or cutting). Broadfoot calculated a 20-foot site index range for each species “…to represent near-virgin site condition.” This value range was intended to capture natural variation in “…local moisture conditions, individual stand characteristics, and genetic differences within species.” A base age of 50 years was used in the generation of site index values (tree height) for all species except cottonwood, which utilized a base age of 30 years.
• Alligator soils: sweetgum (75-95 feet; average 89 feet), Nuttall oak (80-100 feet; average 88 feet), willow oak (80-100 feet; average 88 feet), water oak (75-95 feet; average 83 feet), green ash (70-90 feet; average 80 feet), eastern cottonwood (80-100 feet, average 92 feet), cherrybark oak (80-100 feet; average 86 feet), American sycamore (75-95 feet)
• Sharkey soils: sweetgum (80-100 feet; average 88 feet), Nuttall oak (80-100 feet; average 91 feet), willow oak (85-105 feet; average 92 feet), water oak (80-100 feet; average 85 feet), green ash (75-95 feet; average 80 feet), eastern cottonwood (85-105 feet, average 92 feet).
(Note that cherrybark oak and American sycamore occasionally occur on these soils and may not be suitable in some locations, especially wetter areas.)
Dominant plant species
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sweetgum (Liquidambar styraciflua), tree
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willow oak (Quercus phellos), tree
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Nuttall oak (Quercus texana), tree
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American elm (Ulmus americana), tree
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sugarberry (Celtis laevigata), tree
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green ash (Fraxinus pennsylvanica), tree
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Drummond's maple (Acer rubrum var. drummondii), tree
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water oak (Quercus nigra), tree
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cedar elm (Ulmus crassifolia), tree
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common persimmon (Diospyros virginiana), tree
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greenbrier (Smilax), shrub
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peppervine (Nekemias arborea), shrub
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trumpet creeper (Campsis radicans), shrub
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eastern poison ivy (Toxicodendron radicans), shrub
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possumhaw (Ilex decidua), shrub
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sedge (Carex), grass
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rosette grass (Dichanthelium), grass
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smallspike false nettle (Boehmeria cylindrica), other herbaceous
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Virginia dayflower (Commelina virginica), other herbaceous
State 2
Greentree Reservoir
The Greentree Reservoir (GTR) state is provisionally included in this description due to the level of hydrologic manipulation and management that is generally pursued. Additionally, these structures have widespread distribution and occurrence throughout the Southern Mississippi River Alluvium and have been developed and established on this ecological site.
The principal function and purpose of most GTRs within MLRA 131A is to provide reliable flooded habitat for migrating and wintering waterfowl in one of North America’s irreplaceable migratory corridors, the fabled Mississippi Flyway. The extensive losses of forested habitat coupled with the draining of wetlands and construction of flood control projects throughout the MLRA have made these reservoirs particularly attractive to wildlife, recreationists, and natural resource managers (Fredrickson and Batema, 1992). They occur on both public and private lands (Wigley and Filer, 1989). In general, GTRs consist of floodplain forests that have been leveed, water control structures established, and a water supply constructed to flood targeted locations during tree dormancy, which generally occurs from late fall to late winter. These management units are typically positioned in environments that can be effectively flooded or impounded to a shallow depth, consist of predominantly clayey soils, and support mature bottomland hardwoods with a concentration of red oaks such as Nuttall, willow, water, and cherrybark with pin oak (Quercus palustris) increasing in importance in the northern portions of the MLRA. Red oaks are heralded for providing an energy-rich food source for some waterfowl species. Important soft mast food sources include elm, ash, tupelo (Nyssa spp.), and red maple (Acer rubrum) (Fredrickson and Batema, 1992; Fredrickson, 2005).
The composition and maturity of many forest stands within GTRs likely support characteristics that resemble reference conditions. However, hydrologic regimes and hydroperiods of many GTRs are managed intensively every year with targeted flooding beginning and ending (i.e., drained) on predetermined dates, often coinciding with waterfowl hunting seasons. In many instances, water drawdown is delayed due to logistical limitations and extends into the growing season (Wigley and Filer, 1989; Fredrickson and Batema, 1992). This annual rigor in maintaining water levels differs greatly from natural, periodic flooding regimes and has led to unanticipated single-species and community-level stressors, particularly in areas where this level of yearly management has occurred for more than a decade (Fredrickson and Batema, 1992). Some of the reported impacts include basal swelling of trees, reduced tree vigor, tree mortality, changes in plant composition to predominantly flood tolerant species, poor acorn production, poor tree regeneration, increased windthrow, crown dieback, tree cankers, a higher incidence of insect infestations, and even a decrease in waterfowl usage (Wigley and Filer, 1989; Fredrickson and Batema, 1992; Fredrickson, 2005; Hertlein and Gates, 2005; Heitmeyer et al., 2024). Notably, management of some GTRs have been modified over the years to mimic more natural, periodic flooding cycles with shortened hydroperiods to reverse these types of impacts. Still, the uncertainties of community-level responses and conditions within these impoundments have prompted inclusion of this state.
Note that this state mainly pertains to established GTRs. If there is intent to develop one of these management units, then all Federal and State statutes and regulations pertaining to wetlands and the Nation’s waters and waterways must be followed. All associated regulatory reviews and permits should be completed and obtained before construction activities are pursued.
Community 2.1
Seasonally Impounded Backswamp Forest
This community phase is representative of management extremes where the influence of annual impoundment and extended hydroperiods can lead to demonstrable changes in the plant community. Mounting evidence suggests that extending the hydroperiod on this site beyond natural weather cycles and well into the growing season could induce changes in plant community composition over the long term. Newling (1981) reported a shift towards a more water tolerant community in the understory and herbaceous layers of a GTR forest stand compared to an adjacent reference community that occurred in a natural setting. He noted a significant increase in stem densities of water hickory, overcup oak, eastern swampprivet (Forestiera acuminata), and buttonbush (Cephalanthus occidentalis) along with a reduction in density of possumhaw, sugarberry, grape (Vitis spp.), eastern poison ivy, Carolina coralbead (Cocculus carolinus), climbing dogbane (Trachelospermum difforme), trumpet creeper, American elm, and greenbrier in the GTR. Stiff dogwood (Cornus foemina) was absent in the GTR understory but was relatively abundant in the reference community. Observations by others of a GTR on this ecological site include a reduction in bole volume growth and acorn production of Nuttall oak, decline in tree vigor, and higher incidence of Nuttall oak mortality (Francis, 1983; Schlaegel, 1984). Based on the preceding coupled with observations elsewhere (e.g., Ervin et al., 2006; Heitmeyer et al., 2024), characteristics of GTRs that have been annually impounded and had hydroperiods that extended into the growing season for many years (multiple decades) may be comprised of:
• Predominantly water tolerant species with a higher abundance of overcup oak, water hickory, buttonbush, swampprivet, and planertree
• Lower plant diversity
• Higher incidence of tree mortality (e.g., snags and coarse woody debris)
• Reduced regeneration and presence of important mast producing trees (e.g., red oaks)
• Reduced tree growth rates
The preceding represents a management extreme, but the body of literature cited, which includes detailed studies conducted within long established GTRs, describe these types of plant community alterations. Notably, the higher elevations of this ecological site may preclude severe impacts throughout the site’s distribution within a given GTR. Depending on individual GTR characteristics (e.g., levee elevations, management regimes, and goals), impounded water levels may never inundate the highest elevations for exceedingly long durations, if at all. Such areas may become important reserves for restoring lower and wetter areas that have been impacted from annual flooding. Areas of this site that may be impacted most are the lowest ridges and rises that remain below targeted water levels for very long durations and along the interface of ridges and flats.
State 3
Commercial Forestland
This state consists of two very different community phases and management approaches. Community Phase 3.1 represents forest management and production on this site. A distinguishing feature of this phase is the level of management intensity designed to maximize merchantable goals. Various silvicultural methods are available for selection, and these are generally grouped into even-aged (e.g., clearcutting, seed-tree, and shelterwood) and uneven-aged (e.g., single tree, diameter-limit, basal area, and group selection) approaches (Meadows and Stanturf, 1997). Depending on the method selected, different structural and compositional characteristics of the stand may result. Removal and control of community associates are typically a critical element of production goals. These actions may result in different community or “management phases” (and possibly alternate states) depending on the methods used and desired results. Finding the appropriate approach for a given stand and environment necessitates close consultation with trained, experienced, and knowledgeable forestry professionals. If there is a desire to proceed with this state, it is strongly urged and advised that professional guidance be obtained and a well-designed silvicultural plan developed in advance of any work conducted.
Community Phase 3.2 represents conditions of many stands that have incurred indiscriminate timber harvests (e.g., heavy cutting or diameter-limit harvests of select species) and opportunistic regrowth following such harvests (i.e., no management at any period). Some stands may continue to support a few desirable species and quality stems, but in many instances, affected stands will be comprised of mostly shade tolerant species or trees of desirable species that are defective and fail to meet their maximum potential. (Because of the intensive management required to rehabilitate affected stands, this community phase warrants elevation to a standalone state. This should be considered in future iterations of this site’s development.)
Although this site is well suited for forest production, seasonal wetness imposes severe limitations for some forest operations. The principal management concerns are equipment limitations, plant competition, and seedling mortality. Seasonal wetness and periods of heavy precipitation can impose limitations on heavy equipment usage. If possible, equipment operations are best conducted during drier periods of the year, which minimizes soil damage, compaction, erosion, and helps to maintain productivity. A seasonal high water table that includes ponding or inundation for long periods can kill recently planted seedlings, especially if they are not adapted to withstand these conditions. Additionally, these soils have high shrink-swell potential, which causes deep, wide cracks to develop during droughty periods (USDA-SCS, 1990; USDA-NRCS, 2004; USDA-NRCS, 2006b). Exceedingly long dry periods could cause desiccation of exposed roots, which is another potential source of seedling mortality (Goelz, 2001).
An important caveat of this state is its representation of forest conditions that have retained full site production potential. Currently, transitional pathways to this state originate from another forested state (States 1 and 2), only. Former land uses (alternate states) that result in altered conditions of the soil environment (e.g., land leveling, ditching and drainage) may deleteriously affect predicting and planning for species site selection, tree productivity, and possibly survival of the targeted species. State 7 (Forest Recovery) is representative of forest establishment and growth on locations where soil compaction and reduction of nutrients have occurred due to former land practices. Once a previously affected location has recovered its site potential, transition to this state may be possible. That potential transition is still under review and is currently not shown or addressed in the state and transition model.
Community 3.1
Forest Management
Prescribing a silvicultural system for a given stand depends on species composition and long-term production and postproduction goals (Gardiner et al., 2002). The canopy trees listed in Community Phase 1.1 as “favored in management” are all production options on this site ranging from single species plantations to complex multi-species stands. Amendments to that list are the potential addition of American sycamore (Platinus occidentalis) and a cautionary note concerning cherrybark oak. American sycamore and cherrybark oak have been recorded as occurring occasionally on this site but only sycamore is considered suitable for planting (Broadfoot and McKnight, 1961; Broadfoot, 1976). They are not consistently recorded as associates of the perceived reference community (see Putnam and Bull, 1932; Putnam, 1951; Eyre, 1980). Furthermore, growth may be poor and could lead to challenges if planted, especially cherrybark oak (Broadfoot, 1976; Goelz, 2001). (Species favored in management are indicated below under the "Dominant tree species" section for convenience.)
Broadfoot’s (1976) list of species favored in management consists of taxa that are associates of one of the more highly prized forest types of the Southern Mississippi River Alluvium, the sweetgum – willow oak type (Putnam, 1951). Managing for the oaks of this type may be preferred given the multiple values they provide (e.g., timber and wildlife). However, maintaining that component beyond a single rotation (or harvest) may be the most challenging. Creating conditions that promote oak persistence in future stands require a sufficient advance regeneration component. Ensuring that this future crop is established will require close adherence to a well-designed silvicultural plan, which requires programmatic intermediate operations (e.g., improvement cuttings, thinnings, and other partial cuttings). An even-aged silvicultural system that utilizes the clearcutting regeneration method along with brush management to reduce subsequent competition is typically the advocated approach when harvesting bottomland oak stands (Johnson and Shropshire, 1983; Clatterbuck and Meadows, 1993; Hodges, 1995; Meadows and Stanturf, 1997; Oliver et al., 2005). Of caution, some species that are favored in management may not be suitable for planting in every location of this ecological site. Species that are adapted to drier or better drained environments such as water oak and eastern cottonwood may experience higher seedling mortalities if they are planted in areas that tend to flood or pond for long to very long durations. Additionally, Broadfoot (1976) cautioned against planting oaks in locations where soil pH approaches 7.5, which could occur in some areas supporting Sharkey soils. Therefore, each targeted location should be carefully assessed and examined before costs are incurred and seedlings planted.
Apart from the oaks, the remaining trees that are favored in management are light-seeded species. A variety of silvicultural systems may be implemented to promote production of these species including even-aged and group selection (uneven-aged) approaches (see Meadows and Stanturf, 1997). Eastern cottonwood, however, has different challenges due to its extreme shade intolerance and its inability to cast dense shade over the understory. Due to shade intolerance, it cannot succeed itself naturally and requires mechanical site preparation (or scarification) to expose the soil surface prior to establishing and reestablishing following harvests. The relatively “light shading” that its canopy produces permits invasion of shade tolerant species. Many such stands may have dense midstories and understories of green ash, sugarberry, American elm, and boxelder (Johnson and Shropshire, 1983; Hodges, 1995; Meadows and Stanturf, 1997).
Community 3.2
Non-managed/High-graded
This forest community is directly influenced by former harvesting practices that include repeated single-tree selection or diameter-limit harvests with no additional management activities (e.g., brush management, competitor control, etc.). These practices typically target the highest quality trees of the most desirable species. The result is usually an expansion and in-filling of shade tolerant subcanopy trees. Over time, this practice will lead to a predominantly shade tolerant community that may be comprised of American elm, sugarberry, cedar elm, Drummond’s maple, red mulberry, common persimmon, and possumhaw (Putnam et al., 1960).
Pathway 3.1A
Community 3.1 to 3.2
This pathway includes heavy cutting of the stand that removes the desired species (typically shade intolerant species) of sufficient diameters followed by no management of the residual stand or repeated single-tree harvests (e.g., diameter-limit cuts) that removes the desired species followed by no management of the residual stand. The resulting stand is typically comprised of shade tolerant species with low commercial value.
Pathway 3.2A
Community 3.2 to 3.1
Intensive management will be required to push a shade tolerant community into a more commercially desirable and viable system. Actions will likely require a complete clearcut of the stand followed by repeated brush and competitor control (chemical and mechanical). If there is a lack of seed source, artificial regeneration will likely be required to reintroduce heavy-seeded species (e.g., oaks). Continual competitor control will be needed.
State 4
Cropland
This state is representative of the dominant land use activity on this ecological site, agriculture production. Principal crops grown on these soils are rice (Oryza sativa) and soybeans (Glycine max) with secondary crops consisting of small grains such as wheat (Triticum aestivum) and cotton (Gossypium hirsutum) (Snipes et al., 2005). Specialty crops (e.g., fruits, vegetables, and tree nuts) may be grown locally depending on local hydrology and the soil-site environment.
Suitability of this ecological site to row crops ranges from well suited to poorly suited depending on local flood regimes, drainage patterns, and the targeted crop. These soils have moderate to high available water capacity, organic matter content, and natural fertility with soil reactions that range from very strongly acid to moderately alkaline (Bruce et al., 1958; USDA-SCS, 1990; USDA-NRCS, 2004; USDA-NRCS, 2006b). Applications of fertilizer and lime may not be a necessity everywhere or in every circumstance as these soils are naturally high in phosphorus and potassium and pH levels are generally within a favorable range. Soil tests should be conducted to determine fertilizer, lime, and nitrogen needs on a specific field and for a given crop (USDA-SCS, 1990). Management concerns are largely centered on seasonal high water tables, very slow permeabilities and runoff, delayed plantings, soil compaction under equipment traffic, development of a plow pan, and poor tilth due to the clayey texture. Areas that are prone to flooding or extended periods of wetness may not be suitable for small grain crops or to crops that require planting in April and May. Management measures to ameliorate some of these issues may include conservation tillage or management system; subsoiling to breakup plow pans for dry-land crops (e.g., soybeans); restricting tillage to appropriate soil moisture content; and establishing a drainage system or network in problematic areas (USDA-SCS, 1990; USDA-NRCS, 2004; USDA-NRCS, 2006b). Of caution, subsurface drainage systems (e.g., pipes or tiles) may not be effective in every situation due to very slow permeability or localized flooding (USDA-SCS, 1990). Major components that producers generally develop and plan are proper selection of crop cultivar, pest control, cropping system, tillage methods, nutrient management, and water management (Snipes et al., 2005). Key practices of some cropping systems often include two or more crops grown in a multiyear rotation, which has been documented to disrupt pest cycles. Leaving crop residue on the surface can help to maintain tilth, fertility, and organic matter content – all critical elements of soil quality and health. For monoculture cropping systems, the implementation of well-designed pest and nutrient management systems are imperative (Pringle et al., 2017). (For assistance, interested parties are advised to visit their local NRCS Field Office.)
Three separate management phases comprise this state: Conservation Management (4.1), Transitional Conservation Management (4.2), and Conventional Management (4.3). The three phases consist of varying tillage methods and approaches to soil health management systems.
Community 4.1
Conservation Management
This cropland phase utilizes long term, continuous conservation management systems that include reduced till and cover crops; no-till with cover crops; crop residue retention; and perennial cropping systems. The guiding principles of this system are minimizing soil disturbance and maximizing soil cover, biodiversity, and the presence of living roots. Implementing diverse crop rotations while maintaining these principles can lend to the development of an integrated pest management plan and contribute to overall system resilience.
Of caution, the above-ground crop growth or yields may not be the best tracking mechanism for assessing the efficacy or presence of this management phase. Indicators of these systems are generally determined via soil-site assessments with outcomes that may include enhanced soil aggregate stability, increased soil biological activity, higher organic matter content, and improved water holding capacity and infiltration rates while also alleviating soil compaction and reducing runoff and erosion (Chessman et al., 2019). Additional advantages to this system that have been noted by some producers are reductions in fuel and labor costs and less wear and tear on machinery and equipment.
There are challenges to this management system, especially in situations where tillage may be considered and/or needed to repair weather damage or other detrimental impacts. Implementation of conventional tillage even after long term conservation practices (e.g., no-till) can reset the affected area back to a conventional cropping system. However, those changes can be reversed and a return to a conservation management system is achievable.
Critical conservation practices associated with this phase include cover crops, no-till, and reduced till as the foundational practices. Additionally, this phase may include supporting and site-specific practices to address conservation needs for a given location.
Community 4.2
Transitional Conservation Management
This cropland phase utilizes a hybrid approach that combines conventional methods with conservation practices at specific periods and under specific situations. Practices under this phase may include a combination of conventional till, reduced till, strip till, and the inclusion of cover crops. For instance, perennial crop species could be in a continuous transitional phase where conventional tillage is implemented at the time of planting followed by reduced tillage during the rotation. Planted forage crops could also be included in this phase, especially when part of a crop rotation that utilizes reduced tillage for one crop followed by conventional tillage for a succeeding crop.
The development, implementation, and refinement of nutrient and pest management plans throughout component operations are imperative. Additionally, this phase may include supporting and/or site-specific practices to address conservation needs for a given location.
Community 4.3
Conventional Management
This management phase is representative of conventional cropland where tillage is implemented as an annual component of the production system. As crucial elements of the system, conservation practices such as nutrient and pest management are needed to address fertility requirements and pest concerns within the crop cycle. It is important to note that this phase may develop when tillage is implemented to address damage or for other purposes while under a conservation management system (Community Phase 4.1). There could also be associated, supporting, and site-specific practices that are needed to address specific conservation needs. Specific needs may include grade stabilization structures to control gully erosion, grassed waterways to trap sediment from sheet and rill erosion, or implementing reduced till.
Pathway 4.1A
Community 4.1 to 4.2
Soil disturbance (tillage); reduction of soil health.
Pathway 4.1B
Community 4.1 to 4.3
Conventional tillage, seeding, and fertility management for crops.
Pathway 4.2A
Community 4.2 to 4.1
No-till, cover crops, reduced till-soil health improvements.
Pathway 4.2B
Community 4.2 to 4.3
Conventional tillage, seeding, and fertility management for crops.
Pathway 4.3A
Community 4.3 to 4.2
Reduced till, no-till, and cover crops with soil health improvements as a goal.
State 5
Land Formed Cropland
The gently sloping to undulating ridges of this site typically adjoin level surfaces. This site is often bordered by soils of varying textures and drainage characteristics. Accordingly, inconsistencies in wetness and dryness, ease of operation, and production or yields may occur across a cropped location. An increasingly common practice consists of land forming or leveling surface irregularities into a predetermined and engineered, uniform slope. This practice removes drier and higher features, which are then used to fill wetter and lower positions (e.g., depressions or swales) across the targeted area. Advantages of land leveling may include reduced hazards of erosion and runoff rates, improved surface drainage, and enhanced distribution and conservation of irrigation water. Disadvantages of the practice is a churning of various surface and subsurface materials (former soil horizons) that no longer occur in a predictable or regular pattern. Organic matter content in the surface layer is generally low, and the surface tends to crust and pack after heavy rains (USDA-NRCS, 2006b). One potential hazard that appears to be emerging in some areas is the need for managing surface water runoff. As both irrigated and stormwater runs off leveled fields at uniform rates, surface water tends to collect cumulatively and simultaneously, which places tremendous demands on local drainage systems. Without “in field” structures (natural or artificial) to stagger runoff, the downslope (or lower) ends of some fields tend to back flood thereby contributing to more flooding overall in local watersheds (personal observations).
Immediately following land leveling, the constituent elements of soil health are likely to be absent. In some areas, producers have initiated practices such as applying organic residues (e.g., poultry litter) or growing rice crops for one to two years to rapidly boost fertility and introduce organic matter (via rice biomass) in the surface layer. Over time, the full complement of the management (or community) phases of State 4 may be possible on land leveled fields. They are not repeated or indicated here.
Currently, this state serves as an endpoint in the state and transition model because the ability to predict vegetation response when transitioning to a different state is no longer possible without soil-site investigations for each area of interest. The former soils of this ecological site, including surface and subsurface horizons, will have been redistributed as particles among other former soils depending on the depth of the initial “grade cuts” and leveling efforts.
Community 5.1
Land Leveled Cropland
Some of the crop species and management practices indicated and discussed in State 4 (including all three management phases) may be suitable for establishing on land leveled areas that once supported the soils of this site. However, the type of crops suited for newly leveled areas may ultimately depend on the prevailing soil particle-size distribution and internal drainage characteristics. Former studies on precision leveled fields have noted variabilities and inconsistencies in soil particle-size distributions, bulk density, soil biological properties, and nutrients (Brye et al., 2003; Walker et al., 2003; Brye et al., 2006). Management concerns for this phase may consist of restricted permeability, low organic matter content, and crusting and packing (USDA-NRCS, 2006b). These impacts may be improved by implementing conservation tillage, cover crops, retaining crop residue, and nutrient and pest management strategies.
State 6
Pastureland/Grassland
This state is representative of areas that have been converted to and maintained in pasture or grassland. Limitations of this state are mainly associated with a seasonally high water table and the flooding of areas that are located near active tributaries or prone to back flooding. High water tables over long durations will restrict root growth and establishing plants in particularly wet locations may prove challenging. These soils are suited to most commonly grown forage species except bahiagrass (Paspalum notatum), crimson clover (Trifolium incarnatum), and some cool season annual forage plants. Note that bahiagrass and crimson clover do not respond well where soil reactions are above 6.5 (Houck, 2009; Young-Mathews, 2013). Overall, forage production is considered moderate to high when adequately fertilized and properly managed. Lime may not be a necessity everywhere or in every circumstance. Soil tests should be conducted to determine fertilizer, lime, and nitrogen needs for a specific location (USDA-SCS, 1990).
Given that this ecological site occurs on poorly drained, clayey soils, some forage operations may experience multiple wetness events in a single year. Management concerns are mainly centered on soil compaction due to grazing (USDA-NRCS, 2006b), and overgrazing can lead to numerous bare spots and muddy conditions that effectively reduces or destroys plant establishment and productivity. Planning or prescribing the intensity, frequency, timing, and duration of grazing will be very important on these wetter soils. Of caution, some annual and perennial winter plants naturally growing in wet locations (e.g., sedges, rushes, and some forbs) may be an additional challenge as these are often unpalatable or toxic if consumed.
Flood-prone areas may limit the type of forage suited for this site. In areas that flood on a regular basis, implementing management actions such as planting or overseeding appropriate cool season forage varieties (e.g., ‘Marshall’ ryegrass, Lolium perenne ssp. multiflorum; also known as annual ryegrass) into established warm season grasses at heavy forage rates have been observed to help protect riparian areas from detrimental river or stream scouring (personal observations by Rachel Stout Evans, contributing author). Initiating such remedial actions aid in the recovery and reestablishment of preferred warm season forage following seasonal flooding. (Note that herbicide resistant varieties could be problematic and may warrant reconsideration. Please consult with local NRCS Field Offices for assistance.) Where permissible, a system of artificial drainage or water control structures may be in place to facilitate continued forage production and grazing during wetter periods. Note that the higher elevations of this site may serve as important protection areas for the storage of harvested forage or the holding of livestock when wet or flooded conditions occur on the lower, adjoining flats.
Establishing an effective pasture management program can help minimize degradation of the site and assist in maintaining growth of desired forage. An effective pasture management program includes selecting well-adapted grass and/or legume species that will grow and establish rapidly; maintaining proper soil pH and fertility levels; using controlled grazing practices; mowing at proper timing and stage of maturity; allowing newly seeded areas to become well established before use; and renovating pastures when needed (Rhodes et al., 2005; Green et al., 2006).
This state consists of four community phases that represent a range of forage management options and pasture and hayland condition scenarios. Options range from establishing a forage monoculture for haying to a broad mixture of forage species for production and grazing. It is strongly advised that consultation with local NRCS Service Centers be sought when assistance is needed in developing management recommendations or prescribed grazing practices.
Community 6.1
Monoculture Grassland
This phase is mainly characterized by planting forage species for hay production. Forage plantings generally consist of a single grass species. Native and/or non-native forage species can be seeded and is usually harvested as hay or haylage, although grazing may occur periodically. These environments are generally productive for forage and can provide ecological benefits to control soil erosion. Allowing for adequate rest and regrowth of desired species is required to maintain productivity. Maintenance of monoculture stands also requires control of unwanted species, which will require pest and nutrient management.
Forage suited for this community phase include hybrid and common Bermudagrass (Cynodon dactylon), dallisgrass (Paspalum dilatatum), or possibly sorghum-Sudangrass hybrid (Sorghum bicolor ssp. drummondii) in drier locations. Tall fescue (Schedonorus arundinaceus) may be an option in the northern portions of the basin. The application of fertilizer is generally needed to establish and maintain improved desirable hayfields and pastures. An additional measure to aid production may include prescribed grazing. Implementing limited and monitored grazing can promote deeper root penetration of grasses with the added benefit of greater nutrient and moisture uptake. This synergistic approach can lead to increased production of and may sustain desirable forages.
Conservation practices should include prescribed grazing or forage harvest management, nutrient and pest management, and potentially other site-specific practices.
Community 6.2
Mixed Species System
This community is characterized by mixed species composition of grasses and legumes. Components of this forage system are either planted or they established naturally. Typically, perennial warm-season grasses are the foundation of the stand that are periodically overseeded with adapted cool-season forages. The latter creates an added benefit of extending the grazing season. This community phase can be highly productive for grazing and haying operations and can provide beneficial habitat for some wildlife species.
Maintenance of grass stands also requires a series of management practices such as prescribed grazing, brush management, pest management, and nutrient management to maintain production of the desired species. Prescribed grazing includes maintaining proper grazing or forage heights, timing, and stocking rates. Supporting or facilitating practices such as fences, water lines, and watering facilities could be part of the system that maintains this phase.
Community 6.3
Mixed Species, Non-seeded
This community is characterized by a mixture of native and naturalized non-native species. Forage is usually grazed or harvested as stored forage, hay or haylage. Commonly established species may include Bermudagrass, dallisgrass, and potentially tall fescue in the north.
Stands are generally productive, and forage and grazing management can maintain the community. Healthy stands provide additional benefits by protecting soils from excessive runoff and erosion. However, a common peril associated with this phase is overgrazing, which lowers production and favors less palatable weedy species, especially in areas where livestock congregate. Proper stocking rates and/or grazing systems that allow for adequate rest and plant regrowth are required to maintain productivity. When forage species are afforded adequate recovery time between grazing intervals, they develop deeper root systems and greater leaf area. Conversely, when plants are not allowed to adequately recover, root development will be restricted leading to lower forage and biomass production. Additionally, maintenance of grass stands requires implementing pest management practices to control unwanted weedy and woody species.
Community 6.4
Early Woody Succession
This community is characterized by a diverse composition of grasses and forbs with an increasing presence of woody species (both native and non-native) that are immature and of low stature. Woody species grow quickly on this site and can be difficult and expensive to control. One potentially problematic species may be honeylocust (Gleditsia triacanthos). Putnam (1951) reported honeylocust as being common on old pastures, and the species can be difficult to remove once established. Management to transition this phase to other forage communities of this state is still possible without excessive inputs and effort, particularly if stem diameters remain below 2 inches and are widely scattered (e.g., a density of less than 100 stems per acre). However, if diameters become greater than 3 inches and densities exceed 300 stems per acre, far more investment, effort, and inputs will be required. If brush management measures are not undertaken, the plant community will transition to the Ruderal/Opportunistic Regrowth (Community Phase 7.1) of State 7.
Of note, this community phase is often very beneficial habitat for some wildlife species, especially a specific guild of resident and Neotropical migratory bird species that are habitat-specific on old field to young tree stand habitats.
Pathway 6.1A
Community 6.1 to 6.2
Seeding and/or management for desired species composition.
Pathway 6.1B
Community 6.1 to 6.3
Species management without overseeding.
Pathway 6.2A
Community 6.2 to 6.1
Seeding, fertilizing, management/removal of undesirable species.
Pathway 6.2B
Community 6.2 to 6.3
Species management without overseeding.
Pathway 6.3A
Community 6.3 to 6.1
Seeding, fertilizing, management/removal of undesirable species.
Pathway 6.3B
Community 6.3 to 6.2
Seeding and/or management for desired species composition.
Pathway 6.3C
Community 6.3 to 6.4
Lack of disturbance; no (or infrequent) mowing, herbivory, or brush management; natural succession of woody species.
Pathway 6.4A
Community 6.4 to 6.3
Brush management/removal of unwanted species.
State 7
Forest Recovery
This state is representative of forest recovery in areas that were once under former intensive land use such as long-term row crop cultivation. Characteristics that distinguish this state from other forest states on this site include a suite of soil-site properties that reportedly affect tree growth such as higher soil bulk density due to compaction, presence of a plow pan, lower organic matter content, and reduced fertility (Baker and Broadfoot, 1979; Groninger et al., 1999). Two community phases are provisionally recognized for this state. Community Phase 7.1 represents natural colonization of tree and shrub species without management. Community Phase 7.2 is representative of intentional forest establishment by artificial regeneration or planting.
For Community Phase 7.2, determining the objectives and goals of the future stand is imperative to increase the probability of successful establishment and production of the afforested area. These decisions will ultimately determine the species to be established, preparation requirements, planting density, and post-planting operations (e.g., competitor control, future improvement cuttings and thinnings, regeneration methods, and overall stand health). Since each area targeted for afforestation may have unique or different land use histories, having a clear understanding of the soil-site conditions is essential. Some areas may necessitate a series of soil improvement actions prior to planting. These actions may include subsoiling or deep plowing to breakup plow pans and fertilizing the targeted area. An additional option is to allow the area to undergo fallowing for a predetermined period (Community Phase 7.1) to potentially increase soil organic matter content, enhance soil aggregate stability, increase soil biological activity, and improve water holding capacity and infiltration rates. Controlling competing vegetation (chemical and/or mechanical treatment) will be critical. Post-planting operations and maintenance of the stand can enhance survival, future development, and achieve goals and objectives (see Gardiner et al., 2002).
Finding the appropriate approach for a given environment necessitates close consultation with trained, experienced, and knowledgeable forestry professionals. If there is a desire to proceed with this state, it is strongly urged and advised that professional guidance be obtained and a well-designed afforestation and silvicultural plan developed in advance of any work conducted. For an exceptional review and summarization of the afforestation literature, techniques, and practices within the Southern Mississippi River Alluvium, interested parties are directed to Gardiner et al. (2002).
Community 7.1
Ruderal/Opportunistic Regrowth
This community phase is representative of former working lands (e.g., cropland and possibly high concentration areas of former pastureland) that have fallowed and subsequently undergone natural vegetation colonization. Depending on location, a profusion of growth may initiate within five to ten years of becoming idle - one that typically includes grasses, forbs, woody seedlings and shrubs, and an increasing presence and covering of vines. Initial colonization may be dominant in annuals followed by a shift to perennial vegetation. Shrubs and tree seedlings may appear very early following abandonment, however the rate of colonization and period to stand establishment likely depends on the proximity of established mature stands (Battaglia et al., 1995; Battaglia et al., 2002). If established stands consisting of light-seeded species adjoin fallow fields, colonizing tree species will likely be comprised of those taxa (e.g., elm, green ash, and cottonwood) (Allen, 1990; Stanturf et al., 2001). Some areas may be far removed from established forest stands. Under this scenario, establishment of woody species (especially overstory tree species) may be very slow, and years may be required before stand establishment is reached (Battaglia et al., 1995; Allen, 1997). In fact, natural colonization by some species may be delayed indefinitely with some stands or areas being understocked (Allen, 1997; Battaglia et al., 2002; Groninger, 2005). Heavy-seeded species like oaks may not have an opportunity to colonize available areas due to distance and lack of a dependable dispersing agent (e.g., wildlife and water). Non-native invasive species may become part of the developing stand given the proliferation of exotic plant species over the past century.
It is extremely difficult, if not impossible, to predict the future composition and structure of an abandoned field on this site. Many different environmental factors will influence initial colonization and development trajectories. The following projections are simply based on native plant species reported to occur on the soils of this site. As the young stand matures and eventually enters the stem exclusion stage (crown or canopy closure), the developing stand may be comprised of American elm, sugarberry, green ash, sweetgum, Drummond’s maple, and eastern cottonwood as a minor or secondary component. Oaks that may occur include overcup, willow, and Nuttall. Problematic non-native species that may occur include Japanese honeysuckle (Lonicera japonica), Chinese privet (Ligustrum sinense), and possibly Callery pear (Pyrus calleryana). Vines in the young, developing stand may include greenbrier, eastern poison ivy, trumpet creeper, grape, Virginia creeper (Parthenocissus quinquefolia), peppervine, and American buckwheat vine. As the stand matures decades into the future and the overstory stratifies (i.e., the understory reinitiation stage), shade tolerant species may dominate the stand.
Community 7.2
Afforestation
This community phase is representative of areas planted in tree species that are suited for and favored in management on this ecological site. Preparation of this phase may be initiated immediately following a former land use activity (e.g., State 4) or it may be started following a fallow period (Community Phase 7.1). If afforestation is initiated immediately following years of conventional tillage without soil-site preparation and improvement efforts, potential productivity of the targeted area could be less than optimal (Baker and Broadfoot, 1979; Groninger et al., 1999; Gardiner et al., 2002).
Groninger et al. (1999) utilized the Baker and Broadfoot (1979) model for site evaluation to predict potential productivity of green ash, Nuttall oak, American sycamore, sweetgum, swamp chestnut oak, water oak, and cottonwood on what they termed “marginal soybean lands.” These are croplands occurring on frequently flooded areas that typically produce low soybean yields under conventional tillage. Soils associated with these areas are generally poorly drained, clayey, and typically classified as hydric. The two soil series of this site, Sharkey and Alligator soils, were included for evaluation. Based on information presented in Groninger et al. (1999), site index predictions on soils that had undergone extensive conventional tillage ranged 6 to 20 percent lower than what are reported in Broadfoot (1976) for green ash, Nuttall oak, American sycamore, sweetgum, swamp chestnut oak, and water oak. Comparing the Baker and Broadfoot (1979) estimated site index values of former conventional tilled cropland to the site index values generated from long established forestland are noteworthy (see Community Phase 1.1). The site index predictions in Groninger et al. assumes that no soil-site improvement actions were undertaken. (Note that site index is the height in feet of select tree species at 50 years of growth except for eastern cottonwood which is height in 30 years of growth.)
Over the years, various afforestation innovations have increased the likelihood of success in addition to soil-site amelioration such as planting large, high-quality seedlings with well-developed root systems in an appropriate cover crop (Dey et al., 2010); interplanting seedlings within a fast-growing pioneer species nurse crop (e.g., cottonwood) (Gardiner et al., 2001); and planting companionable species combinations for mixed species stands (Lockhart et al., 2008). The cover crop and nurse crop approaches reportedly help to control rapid overtopping and crowding by competing vegetation and wildlife herbivory (Dey et al., 2010). Finding the appropriate strategy for a given location requires matching the species to the local hydrologic and soil-site environment; determining short- and long-term objectives and goals; and implementing the appropriate management actions at the required intervals.
Several species that frequently occur and are favored in management are likely appropriate for planting on this ecological site. Broadfoot (1976) listed green ash, Nuttall oak, willow oak, sweetgum, and possibly American sycamore and eastern cottonwood as species suitable for planting. The desirability and importance for establishing oaks have prompted many to attempt plantings on sites that were not conducive to oak production. Some of these former attempts likely targeted high pH soils (i.e., nonacid or alkaline) or species selections that were site incompatible (Mike Oliver, personal communication). Broadfoot warned against planting oaks on locations where soil reactions are pH 7.5 or higher and against planting hardwoods at all in areas that remain “waterlogged” for one or more growing seasons. If oaks are planted on this site, plant competition will likely dictate the need for scheduled competitor control efforts that should not be delayed or postponed.
Pathway 7.1A
Community 7.1 to 7.2
Remove undesirable competitors; final soil preparation; establish site-appropriate species (favored in management and suitable for planting).
State 8
Conservation (Herbaceous)
This state is representative of the range of conservation actions that may be implemented and established on this ecological site. Apart from planting trees and managing for forest, one may elect to establish native herbaceous species and manage for predominantly a native grassland; a complex mixture of native grasses and forbs; or a pollinator planting whereby native forbs dominate the mix. In each of these options, it is strongly advised (possibly a programmatic requirement) that the species comprising the planting or seed mix consist of spring, summer, and fall flowering species. Depending on goals and objectives, various conservation programs and practices may be available. For additional information and assistance, please contact or visit the local NRCS Field Office.
Community 8.1
Pollinator Planting/Native Grasses
This community phase represents the establishment of native forbs or wildflowers for pollinator habitat or native grasses. The seed mix for planting may be quite varied depending on objectives and goals. Ideally, the mix includes a wide range of species that flower at various times of the growing season (spring, summer, and fall). Plant species in some pollinator mixes may include but are not limited to beebalm (Monarda spp.), milkweeds (Asclepias spp.), beardtongue (Penstemon spp.), vervain (Verbena spp.), various legumes such as native lespedeza (Lespedeza spp.), Illinois bundleflower (Desmanthus illinoensis), partridge pea (Chamaecrista fasciculata), and a broad assortment of composites such as asters (Symphyotrichum spp.), tickseed (Coreopsis spp.), blazing star (Liatris spp.), coneflower (Rudbeckia spp.), sunflower (Helianthus spp.) among many others. If goals and objectives are to establish native grasses within a forb mix or in a grass-dominant stand, species suitable for planting may include switchgrass (Panicum virgatum), eastern gamagrass (Tripsacum dactyloides), big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium) and Indiangrass (Sorghastrum nutans). Of caution, if eastern gamagrass is chosen to be planted, soil pH must be below 8.0 as the species’ productivity falters under alkaline conditions (Henson, 2012).
Key to the establishment of this phase is initial preparation, seeding rate, planting period, follow-up treatment, and maintenance of the planting. The selection of species to establish on any given area may ultimately depend on size and conditions of the location where the planting will occur, landowner/manager goals and objectives, and the advice and knowledge of the conservation practitioner.
Transition T1A
State 1 to 2
Actions include construction of levees, water control structures established, water supply mechanisms developed, and an effective drainage and discharge system prepared.
Transition T1B
State 1 to 3
Stand composition is heavily altered and managed to favor select species for production (Community Phase 3.1). This transitional pathway also includes heavy timber cutting and/or repeated partial harvests (high-grading) leading to Community Phase 3.2.
Transition T1C
State 1 to 4
Actions include mechanical removal of vegetation and stumps; herbicide treatment of residual plants; and preparation for cultivation.
Transition T1D
State 1 to 6
Actions include mechanical removal of vegetation and stumps; herbicide treatment of residual plants; seedbed preparation; and establishment of desired forage.
Transition T2A
State 2 to 1
Return to or mimic natural flood periodicities and hydroperiods; conduct timber stand improvement practices and vegetation controls; restore and regenerate species that were formerly impacted; may require removal of levees and water control structures and restoring the natural hydrology if drainage ditches were constructed.
Transition T2B
State 2 to 3
Conduct timber stand improvement practices and vegetation controls; restore and regenerate desired commercial species that were formerly impacted; may require removal of levees and obstructions that contribute to prolonged flooding and ponding.
Transition T2C
State 2 to 4
Actions include mechanical removal of vegetation and stumps and control of residual plants; remove or modify preexisting structures to control flooding/ponding; and preparation for cultivation.
Transition T2D
State 2 to 6
Actions include mechanical removal of vegetation and stumps and control residual plants; remove or modify preexisting structures to control flooding/ponding; seedbed preparation; and establishment of desired forage.
Transition T3A
State 3 to 1
This transition represents a return to perceived reference conditions and involves the reestablishment of missing species; the control or removal of exotic species (herbicide and mechanical); stand improvement practices that favors a return of more shade intolerant components.
Transition T3B
State 3 to 2
Actions include construction of levees, water control structures established, water supply mechanisms developed, and an effective drainage and discharge system prepared.
Transition T3C
State 3 to 4
Actions include mechanical removal of vegetation and stumps; herbicide treatment of residual plants; and preparation for cultivation.
Transition T3D
State 3 to 6
Actions include mechanical removal of vegetation and stumps; herbicide treatment of residual plants; seedbed preparation; and establishment of desired forage.
Transition T4A
State 4 to 5
Precision land leveling
Transition T4B
State 4 to 6
Vegetation removal (mechanical/chemical); seedbed preparation; establishment of desired forage; manage for grazing.
Transition T4C
State 4 to 7
Natural succession (Community 7.1) or prep area (plow pan breakup, fertilizing, etc.); planting species appropriate for site (Community 7.2).
Transition T4D
State 4 to 8
Establish select native species suitable for site; prep area for planting (herbicide and/or mechanical).
Transition T6A
State 6 to 4
Actions include mechanical removal of vegetation; herbicide treatment of residual plants; and preparation for cultivation.
Transition T6B
State 6 to 7
Natural succession (Community 7.1) or prepare area (e.g., plow pan breakup, fertilizing, etc.) for planting tree species appropriate for site (Afforestation - Community 7.2).
Transition T6C
State 6 to 8
Establish select native species suitable for site and prepare area for planting (herbicide and/or mechanical).
Transition T7A
State 7 to 4
Cropland establishment: vegetation removal (mechanical/chemical) and preparation for cultivation.
Transition T7B
State 7 to 6
Mechanical removal of vegetation and stumps; herbicide treatment of residual plants; establish desired forage species and manage for grazing.
Transition T8A
State 8 to 4
Vegetation removal (mechanical/chemical) and preparation for cultivation.
Transition T8B
State 8 to 6
Establish desired forage species and manage for grazing.
Transition T8C
State 8 to 7
Natural succession (Community 7.1) or prepare area (e.g., plow pan breakup, fertilizing, etc.) for planting tree species appropriate for site (Afforestation - Community 7.2).
