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 moderately deep soil of Loamy Limestone/Dolomite Upland Woodlands limits the growth of trees and supports an abundance of native grasses and forbs in the understory. While more productive than adjacent glades, these sites were only moderately tall (50 to 65 feet) with a white oak dominated a semi-open overstory with occasional chinkapin oak and northern red oak. Shrubs were scattered within a dense matrix of native grasses and forbs. 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.
Fire played an important role in the maintenance of these systems. It is likely that these ecological sites, along with adjacent glades 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. But the return of fire would have re-opened the woodlands and stimulated the ground flora.
In the long term absence of fire, woody species, such as eastern red cedar and hickory have encroached into these ecological sites. Most of these ecological sites today are dense, and shady with a greatly diminished ground flora. Removal of the younger understory and the application of prescribed fire have proven to be effective restoration methods.
Loamy Limestone/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 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 buckbrush, gooseberry, and Virginia creeper. It also promotes the invasion of eastern red cedar. Grazed sites have a more open understory. In addition, soil compaction and soil erosion from grazing can be a problem and lower site productivity.
These ecological sites are marginally productive, especially when compared to protected slopes and loess covered units. Oak regeneration can be problematic. Maintenance of the oak component will require disturbances that will encourage more sun adapted species and reduce shading effects.
Single tree selection timber harvests are common for this ecological site and 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 beneficial for existing stands whose composition has been highly altered by past management practices. However, without some thinning of the dense stands and application of prescribed fire, the ground flora diversity can be shaded out and diversity of the stand will 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 oak woodland.
The reference state was dominated by chinkapin oak, post oak and white oak. Maximum tree age was likely 150 to 300 years. 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 reference state, with shifts between phases based on disturbance frequency. Reference state woodlands 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.
Community 1.1
White Oak – Chinkapin Oak/Red Bud – Aromatic Sumac/Virginia Wildrye –Little Bluestem
Figure 8. Reference Loamy Limestone/Dolomite Upland Woodland at Graham Cave State Park, near Montgomery City, Missouri
This phase is a woodland with a white oak dominated a semi-open overstory with occasional chinkapin oak and northern red oak. This woodland phase has a two-tiered structure with an open understory with scattered shrubs and a dense, diverse native herbaceous ground flora.
Periodic disturbances including fire, ice and wind created canopy gaps, allowing oak species to successfully reproduce and remain in the canopy. It is likely that this phase burned at least once every 5 years.
Forest overstory. Forest Overstory Composition based on field surveys (species with cover percentages) and Nelson (2010) and field surveys.
Forest understory. Forest Understory Composition based on field surveys (species with cover percentages) and Nelson (2010) and field surveys.
Community 1.2
White Oak – Chinkapin Oak/Red Bud – Aromatic Sumac – Hickory /Virginia Wildrye – Little Bluestem
This phase is similar to community phase 1.1 but oak, hickory and shrub 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.
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 a depauperate 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.
Community 2.1
White Oak – Post Oak – Chinkapin Oak /Aromatic Sumac
This is an even-aged forest management phase. Logging activities are removing higher volumes of white oak causing a decrease in white oak in the canopy and an increase in northern red oak. Large group, shelterwood or clearcut harvests create a more uniform age class structure throughout the canopy layer while also opening up the understory and allowing more sunlight to reach the forest floor.
State 3
Uneven-Age Managed Woodland
Uneven Age Managed Woodland isdense 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. 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.
Community 3.1
White Oak – Hickory – Northern red Oak/Red Bud/ Bottlebrush grass
This is an uneven-aged forest management phase. Selective logging activities are removing higher volumes of white oak causing a decrease in white oak in the canopy and an increase in northern red oak and hickory. Densities numbers, especially more shade tolerant species, are increasing at the lower size-class levels.
State 4
Managed Silvopasture
The Managed Silvopasture State results from managing woodland communities with prescribed fire, selective thinning, and introducing a managed grazing system with livestock. This state can resemble the reference state, with younger maximum tree ages and lower ground flora diversity.
Community 4.1
White Oak – Chinkapin Oak – Black Oak/Little Bluestem
This phase is an agroforestry practice that combines forestry and grazing of domesticated animals in a mutually beneficial way. Advantages of a properly managed silvopasture operation are enhanced soil protection and increased long-term income due to the simultaneous production of trees and grazing animals.
State 5
Grassland
Conversion of woodlands to planted, non-native pasture species such as tall fescue has been common in the Springfield plateau. Low available water, 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 are discontinued, the site will eventually transition to State 2 (Even-Age). Timber Stand Improvement practices can hasten this process.
Community 5.1
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).
Community 5.2
Tall fescue - Broomsedge/Oak Sprouts
This phase is the result of over use, poor grassland and grazing management and lack of adequate nutrient application. Oak sprouts, oak saplings, and invasive species are increasing as a result of poor 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 livestock from sites in this state coupled with uneven-age management techniques will cause a transition to State 3 (Uneven-Age).
Community 6.1
Black Oak – Post Oak – Hickory / Sassafras/Buckbrush
Due to high-grade logging and uncontrolled grazing, this community phase exhibits an over-abundance of hickory and other less economically desirable tree species and weedy understory species such as buckbrush, gooseberry, poison ivy and multi-flora rose. The understory vegetation offers little nutritional value for cattle, and excessive livestock stocking damages tree boles, degrades understory species composition and results in soil compaction and accelerated erosion and runoff.
