Northern Non-Acid Moderately Wet Floodplain

Description

The pre-settlement plant community of this ecological site was largely removed more than 100 years ago, and there are no extant examples of that community. Following decades of land-use impacts, the plant community that returned in areas include several species of broad-leaved deciduous trees commonly referred to as bottomland hardwoods.

Vegetation associated with this site exhibits signs of increasing soil wetness compared to the better drained areas of the floodplain. Species that occur on the drier natural levees and flats and throughout the narrow drainageways of the Loess Hills (e.g., American beech, white oak, tuliptree, and walnut) generally begin to drop out or their abundance decreased. A shift toward species more tolerant of wet conditions (or increased anaerobic conditions) typically occurs.

Given the nonacid soils and the close proximity to the broad floodplains of the Southern Mississippi River Alluvium (MLRA 131A), community composition of this site may be more similar to the nonacid, somewhat poorly drained soils of that MLRA than to the acid alluvial counterpart elsewhere in MLRA 134.

Submodel

Description

This state is characterized by the regeneration or regrowth of a pre-existing forest stand following a major, stand-replacing disturbance. Scale of the disturbance is at the stand level and is greater than one acre in size (Johnson et al., 2009). Potential types of disturbances include catastrophic windstorms, wildfire, silvicultural clearcuts, and particularly destructive ice storms. The resulting, even-aged stand (or single-cohort) is set on a new course of development, which is highly dependent upon several critical factors including: the composition and structure of the stand prior to the disturbance; the degree or intensity of the disturbance; size and configuration of the disturbed area; and distance to seed sources.

Composition and condition of the forest stand prior to a major disturbance may dictate, in large part, future composition of the regenerating stand. Although colonization by new species is expected soon after the disturbance, many of the pre-existing overstory components are anticipated to occupy position in the new, developing stand – their presence arising mainly from stump or root sprouts, advance regeneration, and germination from the seed bank (Oliver and Larson, 1990).

Submodel

Description

This state represents the breadth of forest management activities on this site. Various management or silvicultural methods can lead to very different structural and compositional results within a managed stand. The range of methods are diverse and include even-aged (e.g., clearcut and shelterwood) and uneven-aged (single tree, diameter-limit, basal area, group selection, etc.) approaches and conversion to a pine monoculture. Included within these approaches is an option to use disturbance mechanisms (e.g., TSI, etc.) to reduce competition and achieve maximum growth potential of the desired species. Inherently, these various approaches result in different community or “management phases” and possibly alternate states. The decision to represent these varying approaches and management results into a single state and phase at this time hinges on the need for additional information in order to formulate definitive pathways, management actions, and community responses. Forthcoming inventories and description iterations of this site will provide more detail on this state and associated management phases.

There are moderate limitations to silviculture practices on this site due to seasonal flooding and/or wetness (equipment limitations) and the high productivity of the soils. Management activities may need to be restricted to drier times of the year. The nonacid reactions, high to very high available water capacity, and active to superactive cation exchange capacity collectively contributes to very high productivity of these soils. Therefore, plant competition on this site may be severe and intensive management may be needed to produce highly desirable species such as oak. Broadfoot (1976) warns that if surface layers have reactions above pH 7.5, then the site should be considered “unsuitable” for planting oaks.

Submodel

Description

This state is representative of sites that have been converted to and maintained in pasture and forage cropland, typically a grass – legume mixture. For pastureland, planning or prescribing the intensity, frequency, timing, and duration of grazing can help maintain desirable forage mixtures at sufficient density and vigor (USDA-NRCS, 2010; Green et al., 2006). Overgrazed pastures can lead to soil compaction and numerous bare spots, which may then become focal points of accelerated erosion and colonization sites of undesirable plants or weeds.

Establishing an effective pasture management program can help minimize the rate of weed establishment and assist in maintaining vigorous 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 new seedings to become well established before use; and renovating pastures when needed (Rhodes et al., 2005; Green et al., 2006). It is strongly advised that consultation with State Grazing Land Specialists and District Conservationists at local NRCS Service Centers be sought when assistance is needed in developing management recommendations or prescribed grazing practices.

Submodel

Description

The major limitations to agriculture production is seasonal wetness and occasional flooding, particularly of unprotected areas. Some areas may have artificial drainage systems established. Crops that are often established include cotton, corn, soybean, and small grains.

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