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.
Dry Sandstone Upland Woodlands are dominated by post oak with lesser amounts of black oak and white oak. The canopy is height (50 to 70 feet) is fairly limited and somewhat open (45 to 85 percent canopy closure). Fire played an important role in the maintenance of this system. It is likely that this ecological site 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. Along with the moderate soil depth they would have further limited the growth and dominance of trees, especially eastern redcedar. During fire free intervals, woody understory species increased and the herbaceous understory diminished. The return of fire would open the woodlands up again and stimulate the abundant ground flora.
Woodlands are distinguished from forest, by their relatively open understory, and the presence of sun-loving ground flora species. 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.
Dry Sandstone 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 large herbivores would have effectively kept understory conditions more open, creating conditions more favorable to oak reproduction.
Today, these ecological sites have been cleared and converted to pasture or have undergone repeated timber harvest and domestic grazing. Most existing wooded ecological sites have a younger (50 to 80 years) canopy layer whose species composition and quality has been altered by timber harvesting practices. In the long term absence of fire, woody species, especially eastern redcedar and hickory, encroach into these woodlands. Once established, these woody plants can quickly fill the existing understory increasing shade levels with a greatly diminished ground flora. Removal of the younger understory and the application of prescribed fire have proven to be effective restoration means.
Uncontrolled domestic grazing has also impacted this community, further diminishing the diversity of native plants and introducing species that are tolerant of grazing, such as coralberry, gooseberry, and Virginia creeper. Grazed sites also have a more open understory. In addition, soil compaction and soil erosion related to grazing can be a problem and lower site productivity.
This ecological site is marginally productive. Single tree selection timber harvests are used in this community but often results in removal of the most productive trees (high grading) in the stand leading to poorer quality timber and a shift in species composition away from more valuable oak species. Better planned single tree selection or the creation of group openings can help regenerate and maintain more desirable oak species and increase vigor on the residual trees.
Clearcutting also occurs and results in dense, even-aged stands dominated by oak. This may be most beneficial for existing stands whose composition has been highly altered by past management practices. However, without some thinning of the dense stands and the 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
The historical reference state for this ecological site was old growth woodland. This stage was dominated by post oak and black oak. Periodic disturbances from fire, wind or ice maintained the woodland structure and diverse ground flora species. Long disturbance-free periods allowed an increase in both the density of trees and the abundance of shade tolerant species. Two community phases are recognized in the reference state, with shifts between phases based on disturbance frequency. Reference states are very rare today. Many sites have been converted to non-native pasture (State 5). Others have been subject to repeated, high-graded timber harvest coupled with domestic livestock grazing (State 6). Fire suppression has resulted in increased canopy density, which has affected the abundance and diversity of ground flora. Many reference states have been managed for timber harvest, resulting in either even-age (State 2) or uneven-age (State 3) woodlands.
Community 1.1
Post Oak – Black Oak/Blue Ridge Blueberry – Fragrant Sumac/Little Bluestem - Ticktrefoil
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
Post Oak – Black Oak/Hickory – Blue Ridge Blueberry /Little Bluestem
Pathway P1.1A
Community 1.1 to 1.2
No disturbance (10+ yrs)
Pathway P1.2A
Community 1.2 to 1.1
Disturbance (fire, wind, ice) every 5-10 years
State 2
Even-Age Managed Woodland
This state starts with a sequence of early seral mixed oak woodlands, which mature over time. These woodlands tend to be rather dense, with an underdeveloped understory and ground flora. Thinning can increase overall tree vigor and improve understory diversity. However, in the absence of fire, the diversity and cover of the ground flora is still diminished. Continual timber management, depending on the practices used, will either maintain this state, or convert the site to uneven-age (State 3) woodlands. Prescribed fire without extensive timber harvest will, over time, cause a transition to Fire Managed Oak Woodlands (State 4).
Dominant resource concerns
Community 2.1
Black Oak – Post Oak /Aromatic Sumac
State 3
Uneven-Age Managed Woodland
Uneven-Age Managed Woodlands resemble their reference state. The biggest difference is tree age, most being only 50 to 90 years old. Composition is also likely altered from the reference state depending on tree selection during harvest. In addition, without a regular 15 to 20 year harvest re-entry into these stands, they will slowly increase in more shade tolerant species and white oak will become less dominant. Uneven Age Managed Woodland is also dense because of fire suppression, but less so than the Even-Age Managed state. Consequently, the woodland ground flora is less suppressed and structural diversity is better maintained. Without periodic disturbance, stem density and fire intolerant species, like hickory, increase in abundance.
Dominant resource concerns
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Plant productivity and health
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Plant structure and composition
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Terrestrial habitat for wildlife and invertebrates
Community 3.1
Black Oak – Hickory/Sassafras/ Woodland Brome
State 4
Fire Managed Oak Woodland
The Fire Managed Oak Woodland state results from managing woodland communities in states 2 or 3 with prescribed fire. This state resembles the reference state, with younger maximum tree ages and lower ground flora diversity.
Dominant resource concerns
Community 4.1
Post Oak – Black Oak/Little Bluestem
State 5
Grassland
Type conversion of woodlands to planted, non-native pasture species such as tall fescue has been common in the Springfield plateau. Steep slopes, abundant surface fragments, low organic matter contents and soil acidity make non-native pastures difficult to maintain in a healthy, productive state on this ecological site. If grazing and active pasture management is discontinued, the site will eventually transition to State 2 (Even-Age Managed). Timber Stand Improvement practices can hasten this process.
Community 5.1
Tall Fescue - Red Clover
Dominant resource concerns
Community 5.2
Tall fescue - Broomsedge/Oak Sprouts
Dominant resource concerns
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Sheet and rill erosion
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Ephemeral gully erosion
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Nutrients transported to surface water
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Plant productivity and health
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Plant structure and composition
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Terrestrial habitat for wildlife and invertebrates
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Feed and forage imbalance
Pathway P5.1A
Community 5.1 to 5.2
Over grazing; no fertilization
Pathway P5.2A
Community 5.2 to 5.1
Brush management; grassland seeding; grassland management
State 6
High-Graded/Grazed Woodland
Wooded sites subjected to repeated, high-graded timber harvests and domestic grazing transition to this State. This state exhibits an over-abundance of hickory and other less desirable tree species, and weedy understory species such as buckbrush, gooseberry, poison ivy and Virginia creeper. The vegetation offers little nutritional value for cattle, and excessive stocking damages tree boles, degrades understory species composition and results in soil compaction and accelerated erosion and runoff. Exclusion of cattle from sites in this state coupled with uneven-age management techniques will cause a transition to State 3 (Uneven-Age Managed).
Community 6.1
Black Oak – Post Oak - Hickory/Sassafras/Buckbrush
Transition T1A
State 1 to 2
Even-aged management; fire suppression
Transition T1B
State 1 to 3
Fire suppression; uneven-age management
Transition T1C
State 1 to 5
Clearing; pasture planting; grassland management
Transition T1D
State 1 to 6
Poorly planned harvest; uncontrolled grazing
Restoration pathway R2A
State 2 to 1
Prescribed fire; extended rotations
Transition T2A
State 2 to 3
Uneven-age management
Transition T2B
State 2 to 4
Prescribed fire; thinning
Restoration pathway R3A
State 3 to 1
Uneven-age management; extended rotations
Transition T3A
State 3 to 2
Even-age management
Transition T4A
State 4 to 2
Uneven-age management; fire suppression
Restoration pathway T4B
State 4 to 3
Even-age management; fire suppression
Transition T5A
State 5 to 2
Tree planting; long-term succession; no grazing
Transition T6A
State 6 to 5
Clearing; pasture planting; grassland management
