Ecological dynamics
Information contained in this section was developed using historical data, professional experience, field reviews, and scientific studies. The information presented is representative of very complex vegetation communities. Key indicator plants, animals and ecological processes are described to help inform land management decisions. Plant communities will differ across the MLRA because of the naturally occurring variability in weather, soils, and aspect. The Reference Plant Community is not necessarily the management goal. The species lists are representative and are not botanical descriptions of all species occurring, or potentially occurring, on this site. They are not intended to cover every situation or the full range of conditions, species, and responses for the site.
The somewhat shallow soils of Calcareous Dolomite Upland Woodlands limited the growth of trees and supported an abundance of native grasses and forbs in the understory. Rather short (35 to 50 feet) chinquapin oaks dominated an open overstory, with occasional white ash, blue ash and Shumard oak. Shrubs were scattered within a dense matrix of native grasses and forbs.
Fire played an important role in the maintenance of these systems. It is likely that these ecological sites, along with adjacent glades and woodlands burned at least once every 5 years. These periodic fires kept woodlands open, removed the litter, and stimulated the growth and flowering of the grasses and forbs. They would have also further limited the growth and dominance of trees, especially eastern redcedar. During fire free intervals, woody species would have increased and the herbaceous understory diminished.
Most of these ecological sites today are denser, and shadier with a greatly diminished ground flora. In the long term absence of fire, woody species, especially eastern redcedar have encroached into these ecological sites. Removal of the younger understory by thinning and the application of prescribed fire have proven to be effective restoration methods. Characteristic plants in the ground flora can be used to gauge the restoration potential of a stand along with remnant open-grown old-age trees, and tree height growth.
Calcareous Dolomite Upland Woodlands were also subjected to occasional disturbances from wind and ice, as well as grazing by native large herbivores, such as bison, elk, and white-tailed deer. Wind and ice would have periodically opened the canopy up by knocking over trees or breaking substantial branches off canopy trees. Grazing by native herbivores would have effectively kept understory conditions more open, creating conditions more favorable to oak reproduction and sun-loving ground flora species.
Uncontrolled domestic grazing has also impacted these communities, further diminishing the diversity of native plants and introducing species that are tolerant of grazing, such as coralberry, gooseberry, and Virginia creeper. It also promotes the invasion of eastern redcedar. Grazed sites have a more open understory. In addition, soil compaction and soil erosion related to grazing can be a problem and lower site productivity. These ecological sites are not productive and as a consequence timber harvesting is limiting. Without some thinning of the stands and application of prescribed fire, the ground flora diversity can be shaded out and diversity of the stand may suffer.
A State and Transition Diagram follows. Detailed descriptions of each state, transition, plant community, and pathway follow the model. This model is based on available experimental research, field observations, professional consensus, and interpretations. It is likely to change as knowledge increases.
State 1
Reference
Historically, these woodlands occurred occur on upland summits, shoulders and backslopes. The restricted soil depth, droughty conditions, and native grasses made them susceptible to frequent fires, once every 3 to 5 years. Consequently, fire-tolerant Shumard oak and chinkapin oak dominated the open-canopy overstory. The understory consisted of a dense cover of native grasses and forbs. Tree height was 40 to 50 feet, and canopy closure 40 to 80 percent. During fire-free intervals, eastern red cedar, along with hickory and oak sprouts, increased in abundance and competed with the herbaceous ground flora, creating brushy woodland (community phase 1.2). However, the return of fire would re-open the woodland and promote the ground flora.
Community 1.1
Chinkapin Oak – Shumard Oak/Fragrant Sumac /Little Bluestem – Hairy Sunflower
This phase has an overstory that is dominated by old growth chinkapin oak and Shumard oak with hickory and northern red oak and post oak also present. This woodland community has a two-tiered structure with an open understory and a dense, diverse herbaceous ground flora.
Forest overstory. The Overstory Species list is based on field reconnaissance as well as commonly occurring species listed in Nelson 2010; names and symbols are from USDA PLANTS database.
Forest understory. The Understory Species list is based on field reconnaissance as well as commonly occurring species listed in Nelson 2010; names and symbols are from USDA PLANTS database.
Community 1.2
Chinkapin Oak – Shumard Oak/Eastern Redcedar – Fragrant Sumac /Little Bluestem – Hairy Sunflower
This phase is similar to community phase 1.1 but oak, eastern redcedar and hickory understory densities are increasing due to longer periods of fire suppression. Displacement of some grasses and forbs may be occurring due to shading and competition from the increased densities of oak and hickory saplings in the understory.
Pathway P1.1A
Community 1.1 to 1.2
This pathway is the result of fire-free interval 10-20 years.
Pathway P1.2A
Community 1.2 to 1.1
This pathway is the result of a fire 3-10 year cycle being re-established.
State 2
Fire Excluded Woodland
Fire suppression has allowed these previously open woodlands to become dense with less fire-tolerant trees and saplings such as eastern redcedar, black oak, and hickory. The dense, shaded conditions and lack of fire has caused the ground flora to decrease in cover and diversity. Fragrant sumac often forms a dense shrub understory under these conditions. However, many of the original herbaceous species persist as small plants or in the seed bank. Consequently, thinning of the woody species and the re-introduction of fire has shown these communities to be exceptionally resilient, and a return, after a period of many years, to the reference condition is possible.
Community 2.1
Post Oak - Chinkapin Oak – Shagbark Hickory/ Ash & Hickory Saplings/Fragrant Sumac
This is the only phase associated with this state at this time. See the corresponding state narrative for details.
State 3
Fire Excluded/Logged/Heavily Grazed Woodland
In addition to fire exclusion, many of these sites have been subjected to heavy grazing by domestic livestock and periodic logging. Like State 2, these areas are dense and shady with a diminished ground flora. In addition, grazed areas exhibit a lower diversity of native ground flora species and an increased abundance of eastern redcedar and other invasive natives such as coralberry. Like State 2, restoration using thinning and fire is possible, but will take longer and require more effort. Restricting livestock access and eliminating logging will be necessary for successful restoration.
Community 3.1
Post Oak – Black Oak – Shagbark Hickory/ Eastern Redcedar & Hickory Saplings/Coralberry
This is the only phase associated with this state at this time. See the corresponding state narrative for details.
State 4
Grassland
Conversion of other states to non-native cool season species such as tall fescue, orchard grass, and red clover has been common. Occasionally, these pastures will have scattered oaks. Long term uncontrolled grazing can cause significant soil erosion and compaction. A return to the reference state may be impossible, requiring a very long term series of management options. If oak sprouting is left unchecked and grazing is eliminated or reduced then over time this state will transition to a fire excluded woodland or to a high-graded/grazed woodland.
Community 4.1
Tall Fescue - Red Clover
This phase is well managed grassland, composed of non-native cool season grasses and legumes. Grazing and haying is occurring. The effects of long-term liming on soil pH, and calcium and magnesium content, is most evident in this phase. Studies show that these soils have higher pH and higher base status in soil horizons as much as two feet below the surface, relative to poorly managed grassland and to woodland communities (where liming is not practiced).
Dominant resource concerns
Community 4.2
Tall fescue - Broomsedge/Oak Sprouts
This phase is the result of poor grassland management. Over grazing and little fertility application has allowed broomsedge and oak sprouts to increase in cover and density reducing overall forage quality and site productivity. Soil pH and bases such as calcium and magnesium are lower, relative to well-managed pastures.
Dominant resource concerns
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Ephemeral gully erosion
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Pathogens and chemicals from manure, biosolids, or compost applications transported to surface water
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
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Terrestrial habitat for wildlife and invertebrates
Pathway P4.1A
Community 4.1 to 4.2
This pathway is the result of over grazing and lack of proper grassland management.
Pathway P4.2A
Community 4.2 to 4.1
This pathway is the result of brush management, grassland re-seeding and proper grassland management.
Transition T1A
State 1 to 2
This is a gradual transition that results from extended, disturbance-free periods of roughly 50 years or longer. Selective logging is also occurring.
Transition T1B
State 1 to 3
This transition is the result of high-grade logging, uncontrolled domestic livestock grazing and fire suppression.
Restoration pathway R2A
State 2 to 1
This restoration pathway is the result of the systematic application of prescribed fire. Mechanical thinning may also be used along with understory removal.
Transition T2B
State 2 to 3
This transition is the result of high-grade logging and uncontrolled domestic livestock grazing.
Transition T2A
State 2 to 4
This transition is the result of clearing and conversion to non-native cool season grassland.
Transition T3A
State 3 to 2
This transition results from the cessation of cattle grazing.
Transition T3B
State 3 to 4
This transition is the result of clearing and conversion to non-native cool season grassland.
Transition T4A
State 4 to 2
This is a gradual transition that results from extended, disturbance-free periods of roughly 50 years or longer, selective logging, tree planting and no grazing.
Transition T4B
State 4 to 3
This transition is the result of light intermittent grazing, long idle periods and increased woody growth and development.
