Western Fragipan Uplands

Description

The pre-settlement plant community of this ecological site was largely removed more than 150 years ago, and there are no extant examples remaining. However, inferences over the structure and dynamics of that system are drawn based on landscape position, soils, and existing community components.

Clark et al. (1974) classed the community of this site as a Mixed Oak – Hickory forest. Based on the site's distribution, varying structural and compositional characteristics likely occurred. A richer community comprised of several species of oak likely dominated the site on the southern end of Crowley’s Ridge where the loess mantle is thickest. A drier oak – hickory community with local inclusions of shortleaf pine and black hickory may have occurred toward the northern end of the Ridge where thinner loess deposits predominate. This range of compositional differences may have also been reflected in community structure with the southern end of the site exhibiting moderately open woodland to forest conditions and the northern end having an open woodland profile. The occurrence of fire and fire frequency may have also varied between the southern and northern extent of this site. The southern end of the deep loess country may have been more “fire sheltered” due to the dissection of the landscape as evidenced by numerous ravines. Either the absence of fire or a long fire return interval would have contributed to more closed canopy conditions. Conversely, the drier conditions of the northern end of the ridge likely led to higher fire frequencies, which would have fostered woodland conditions and created opportunities for fire adapted species such as shortleaf pine to filter into the community as occasional components.

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 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).

If the intensity of the disturbance only removed the overstory and damage to the understory strata was light, then understory components of advance regeneration may proliferate in the new opening. This may be a desired condition if managing for an oak shelterwood harvest and subsequent oak recruitment. However, this scenario is particularly problematic in high-graded stands.

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Description

Forests in this state have undergone repeated select harvests over time. Actions leading to this condition consist of removing the biggest and best trees of the most desirable species and leaving low-quality trees (damaged and deformed) and undesirable species. This action, conducted repeatedly, can cause tremendous shifts in species composition and can decrease the vigor and health of the residual stand. Without implementing carefully prescribed management actions, species composition of extreme high-graded stands may remain in a highly altered condition for many decades, even after large, stand-replacing disturbances resets “successional opportunity.”

Today, this vegetation state probably represents the conditions of many forest stands throughout the distribution of this site. Local stands in which desirable species such as high quality white, cherrybark, and northern red oaks were repeatedly targeted often results in sites with proportionally more hickory, undesirable oaks (e.g., post oak), and a midstory of hophornbeam.

Because “overgrazed woods” often consists of components very similar to high-graded stands, uncontrolled livestock access to forests is also included in this state. This does not take into account carefully prescribed and/or managed forms of forest grazing (e.g., agroforestry or silvopasture), which generally has a mutual goal of providing quality forage and productive forest management. The conditions considered and represented here are the extreme cases of long-term forest grazing; this form of uncontrolled access has been referred to as “turning livestock into the woods” (Brantly, 2014).

A single community phase is selected to represent the breadth of conditions that may be anticipated in stands having been high-graded and with uncontrolled livestock access.

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. Included within these approaches is an option to use disturbance mechanisms (e.g., fire, 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 at this time hinges on the need for additional information in order to formulate definitive pathways, management actions, and community responses. Forthcoming inventories and descriptions of this site will provide more detail on this state and associated management phases. Currently, this state is represented by two distinctly different management options: oak management and conversion to pine monoculture.

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

Agriculture production is generally a minor state or land use on this site due to the narrowness of some of the ridgetops and the dissected landscape. Most production is limited to broader interfluves and divides. Adapted crops on this site include soybeans, grain sorghum, and winter small grains.

There are a few orchards that have been established on some of the broader interfluves of this site. Of the active orchards that have been observed, peach production may be among the most important.

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