State 1
Reference

The reference state was dominated by white oak associated with red oak and other mixed hardwoods. Maximum tree age was likely 150 to 300 years. Periodic disturbances from fire, wind or ice maintained the dominance of white oak by opening up the canopy and allowing more light for white oak reproduction. Long disturbance-free periods allowed an increase in more shade tolerant species such as northern red oak and sugar maple. Two community phases are recognized in this state, with shifts between phases based on disturbance frequency. The reference state can be found in scattered locations throughout the MLRA. Some sites have been converted to grassland (State 4). Others have been subject to repeated, high-graded timber harvests coupled with uncontrolled domestic livestock grazing (State 5). Fire suppression throughout the region has resulted in increased canopy density, which has affected the abundance and diversity of ground flora. Many reference sites have been effectively managed for timber harvesting, resulting in either even-age (State 2) or uneven-age (State 3) managed forests depending upon the removal intensity and the species selection.

Community 1.1
White Oak – Red Oak/Eastern Hop Hornbeam – Ohio Buckeye / Harbinger of Spring – May Apple

Figure 10. Reference state with overstory dominated by white oak and northern red oak - photo NRCS

Figure 11. White oak dominated canopy at Hungry Mother Conservation Area, Howard County, Missouri - photo from MDC

This community is one of the more productive upland forests in the MLRA. While the overstory is dominated by white oak and northern red oak, hickories can also be common. This forest community has a multi-tiered structure, and a canopy that is 75 to 100 feet tall with 80 to 100 percent closure. The sub-canopy and understory are well developed, with eastern hop hornbeam and Ohio buckeye (Iowa) as a dominant understory species. A moderate abundance of shade tolerant forest generalists, such as May apple, ferns, tick trefoils and white snakeroot cover the ground.

Forest overstory. White oak and red oak dominate with scattered hickory and black oak.

Forest understory. The understory layer is well-developed with white ash, eastern hop hornbeam, Ohio buckeye and haws. The ground flora has many spring ephemerals and other shade loving herbaceous plant species.

Community 1.2
White Oak – Red Oak / Sugar Maple – Ohio Buckeye/ Harbinger of Spring – May Apple

Figure 12. White oak dominated reference site at Rebels Cove Conservation Area, Schuyler County, MO - photo from MDC

This phase is similar to community phase 1.1 but red oak and hickory densities are increasing due to longer periods of fire suppression (>20 years) and lack of natural disturbances such as ice and wind. Displacement of some less shade tolerant grasses and forbs such as nodding fescue and goldenrods along with lower densities of most species may be occurring due to shading and competition from the increased densities of oak, maple and hickory saplings in the mid-story.

Forest overstory. White oak and red oak dominate with scattered hickory and sugar maple.

Forest understory. This woodland community has a multi-tiered structure due to lack of disturbance activities. The understory layer is well-developed with maple, white ash, eastern hop hornbeam, Ohio buckeye and haws. The ground flora has many spring ephemerals and other shade loving herbaceous plant species.

Pathway 1.1A
Community 1.1 to 1.2

White Oak – Red Oak/Eastern Hop Hornbeam – Ohio Buckeye / Harbinger of Spring – May Apple

White Oak – Red Oak / Sugar Maple – Ohio Buckeye/ Harbinger of Spring – May Apple

Over time with the absence of disturbance, more shade tolerant species such as sugar maple (black maple in Iowa), bitternut hickory, white ash, basswood and others increase in importance and add structural diversity to the system. In addition, more shade-loving forest shrub (e.g., pawpaw) and herbaceous (e.g., bloodroot) species also increase

Pathway 1.2A
Community 1.2 to 1.1

White Oak – Red Oak / Sugar Maple – Ohio Buckeye/ Harbinger of Spring – May Apple

White Oak – Red Oak/Eastern Hop Hornbeam – Ohio Buckeye / Harbinger of Spring – May Apple

With periodic disturbances, such as fire, ice and wind that create canopy gaps, white oak and red oak are allowed to successfully reproduce and enter the canopy. Over time, these disturbance events result in a community phase transition back to the phase 1.1

State 2
Even-Age Managed Forest

This forest tends to be rather dense with an even-aged overstory and an under developed understory and ground flora. Thinning can increase overall tree vigor and improve understory diversity. Continual timber harvesting, depending on the practices used and age classes removed, will either maintain this state, or convert the site to uneven-age (State 3) forests. This state can be restored to a reference state by modifying or eliminating timber harvests, extending rotations, incorporating selective thinning, and re-introducing prescribed fire. (See Ecological Dynamics section for caution on sites with invasive non-native species of earthworms)

Community 2.1
White Oak – Red Oak/ Eastern Hop Hornbeam / Pennsylvania Sedge

Figure 13. Even-aged shelterwood harvest - photo from USDA Forest Service

This is an even-aged forest management phase. Logging activites are removing higher volumes of white oak causing a decrease in white oak in the canopy and an increase in 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.

Forest overstory. Red oak and white oak are common overstory species along with an hickory. Canopy levels can approach 90 percent.

Forest understory. Rather dense ground cover dominated by forbs and shrubs especially after harvests.

Community 2.2
White Oak – Red Oak/ Eastern Hop Hornbeam – Ohio Buckeye / Pennsylvania Sedge

With cessation of harvesting and no other management inputs this community phase will slowly increase in more shade tolerant species such as hickories, white ash and maple. Over time white oak may become less dominant.

Forest overstory. White oak and red oak are common. Hickory species are increasing in the overstory.

Forest understory. In the long term absence of disturbance, oak and hickory saplings, black cherry and hornbeam encroach into the understory of these woodlands.

Pathway 2.1A
Community 2.1 to 2.2

This pathway results in a cessation or reduction of harvesting frequencies.

Pathway 2.2A
Community 2.2 to 2.1

Re-initiation of harvesting and other forest management activities will transition this community phase back to community phase 2.1.

State 3
Uneven-Age Managed Forest

An uneven-age managed forest can resemble the reference state. The primary 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 harvests and disturbance activities. Without a regular 15 to 20 year harvest re-entry into these stands, they will slowly increase in more shade tolerant species such as sugar maple (black maple in Iowa) and white oak will become less dominant. This state can be restored to a reference state by modifying timber harvests, extending rotations, incorporating selective thinning, and re-introducing prescribed fire. (See Ecological Dynamics section for caution on sites with invasive non-native species of earthworms)

Community 3.1
Red Oak – White Oak /Sugar Maple Saplings/ Ferns

Figure 14. Un-evenaged selective harvesting - photo from Dwyer Forestry Consulting

This is an uneven-aged forest management phase. Selective logging activites are removing higher volumes of white oak causing a decrease in white oak in the canopy and an increase in red oak. Densities numbers, especially more shade tolerant species, are increasing at the lower size-class levels.

Forest overstory. Red oak and white oak dominate the overstory.

Forest understory. Maple, oak and hickory saplings, black cherry, Ohio buckeye and hop hornbeam are common understory species.

Community 3.2
Red Oak – White Oak – Sugar Maple/Ohio Buckeye – Pawpaw / Ferns

With cessation of harvesting and no other management inputs this community phase will slowly increase in more shade tolerant species such as hickories, white ash, red oak and maple in both the canopy layer and the understory.

Forest overstory. Red oak and white oak along with increasing densities of maple dominate the overstory.

Forest understory. In the long term absence of disturbance, maple, oak and hickory saplings, black cherry, Ohio buckeye and hop hornbeam encroach into the understory of these woodlands.

Pathway 3.1A
Community 3.1 to 3.2

This pathway results in a cessation or reduction of harvesting frequencies.

Pathway 3.2A
Community 3.2 to 3.1

Re-initiation of harvesting and other forest management activities will transition this community phase back to community phase 2.1.

State 4
Grassland

Conversion of forests to planted, non-native cool season grasses and legumes has been common. Without proper grassland management these ecological sites are challenging to maintain in a healthy, productive state. With over grazing and cessation of active pasture management, tall fescue, white clover and multi-flora rose will increase in density. In some instances, this state has been converted to native warm season grasses, primarily big bluestem, switchgrass, and Indian grass or pure stands of single species.

Community 4.1
Cool Season Grasses – Legumes

Figure 15. Well-managed cool season pasture near Lake Wapello State Park, Iowa - photo from MDC

This phase is a 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 (phase 4.2) and to woodland communities (where liming is not practiced).

Community 4.2
Tall fescue – White Clover/Multi-flora Rose

Figure 16. Cool season pasture showing weedy invasion due to poor management near Bloomfield, Iowa - photo from MDC

This phase is the result of poor grassland management. Over grazing and inadequate or no fertility application has allowed tall fescue, multi-flora rose, thistle and other weedy species to increase in cover and density reducing overall forage quality and site productivity. White clovers such as ladino and alsike will decrease or go away with no fertilization and overgrazing although Dutch white clover will leave last. Soil pH and bases such as calcium and magnesium are lower, relative to well-managed pastures (Phase 4.1).

Community 4.3
Native Warm Season Grasses

Figure 17. Native grasses and legumes on CRP land in southern Iowa - photo from NRCS

In some instances, this state has been converted to native warm season grasses, primarily big bluestem, switchgrass, and Indian grass or pure stands of single species. These sites are typically converted through a federal cost share program such as the Conservation Reserve Program (CRP) or the Environmental Quality Incentives Program (EQIP). Some sites are associated with an active rotational grazing system.

Pathway 4.1A
Community 4.1 to 4.2

Cool Season Grasses – Legumes

Tall fescue – White Clover/Multi-flora Rose

This pathway results from over grazing and cessation of active pasture management.

Pathway 4.2A
Community 4.2 to 4.1

Tall fescue – White Clover/Multi-flora Rose

Cool Season Grasses – Legumes

To return to Community Phase 4.1, requires brush management, grassland seeding, rotational grazing, and integrated pest management.

State 5
. High-Graded/Grazed Forest

Reference or managed forested states subjected to repeated, high-grading timber harvests and uncontrolled cattle grazing transition to this degraded state. This state 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 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. Browsing by goats using good rotational management can open up the shrub layer, eliminate many of the weedy species and increase both native herbaceous vegetation and may induce regeneration of oak and hickory species. Cessation of active logging and exclusion of livestock from sites in this state will create an idle phase that experiences an increase in black cherry and Ohio buckeye in the understory layer. Transition back to either an even-age managed or uneven-age managed forest will required dynamic and sustained forest stand improvements, cessation of grazing, and selective thinning of overstory and understory canopies. (See Ecological Dynamics section for caution on sites with invasive non-native species of earthworms)

Community 5.1
Black Oak-Hickory/Hickory saplings -Gooseberry-Multiflora Rose/Fragile Fern-Jack in the pulpit

Figure 18. Actively grazed woodland creating an open understory - photo from NRCS

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.

Forest overstory. Canopy exhibits an over-abundance of hickory and other less economically desirable tree species such as black oak.

Forest understory. Over time, understory species such as buckbrush, gooseberry, poison ivy and multi-flora rose increase in density.

Community 5.2
Black Oak- Hickory/Black Cherry- Gooseberry / Fragile Fern – Jack in the pulpit-Geranium

Figure 19. Lamson Woods State Preserve showing a high-graded formerly grazed woodland near Fairfield, Iowa - photo from MDC

Cessation of active logging and reduction in grazing intensity will create an idle phase that experiences an increase in black cherry and Ohio buckeye and weedy species such as buckbrush and gooseberry in the understory layer.

Forest overstory. Canopy exhibits an over-abundance of hickory and other less economically desirable tree species such as black oak.

Forest understory. Understory densities levels are increasing. Species such as black cherry, buckbrush, gooseberry, poison ivy and multi-flora rose are common.

Pathway 5.1A
Community 5.1 to 5.2

Black Oak-Hickory/Hickory saplings -Gooseberry-Multiflora Rose/Fragile Fern-Jack in the pulpit

Black Oak- Hickory/Black Cherry- Gooseberry / Fragile Fern – Jack in the pulpit-Geranium

This pathway results from cessation of active logging and periodic exclusion of livestock or reduction in grazing intensity.

Pathway 5.2A
Community 5.2 to 5.1

Black Oak- Hickory/Black Cherry- Gooseberry / Fragile Fern – Jack in the pulpit-Geranium

Black Oak-Hickory/Hickory saplings -Gooseberry-Multiflora Rose/Fragile Fern-Jack in the pulpit

This pathway results in a return to unrestricted logging activity and increased grazing intensities and frequencies.

Transition 1A
State 1 to 2

Fire suppression and even-aged forest timber management and harvesting will result in a transition to community phase 2.1.

Transition 1B
State 1 to 3

Fire suppression and uneven-aged forest timber management and harvesting will result in a transition to community phase 3.1.

Transition 1C
State 1 to 4

Clearing, pasture planting and grassland management will result in a transition to community phase 4.1.

Transition 1D
State 1 to 5

High grade logging and uncontrolled grazing will result in a transition to community phase 5.1.

Restoration pathway 1B
State 2 to 1

This state can be restored to a reference state by modifying or eliminating timber harvests, extending rotations, incorporating selective thinning and allowing long-term succession to occur.

Transition 2A
State 2 to 3

Thinning and selective harvesting will result in a transition to an unevenaged forest stand.

Transition 2B
State 2 to 5

High-grade harvesting and introduction of uncontrolled grazing will cause a transition to community phase 5.1

Restoration pathway 1A
State 3 to 1

This state can be restored to a reference state by modifying or eliminating timber harvests, extending rotations, incorporating selective thinning and allowing long-term succession to occur.

Transition 3A
State 3 to 2

Thinning and large group harvesting will result in a transition to an evenaged forest stand.

Transition 3B
State 3 to 5

High-grade harvesting and introduction of uncontrolled grazing will cause a transition to community phase 5.1

Transition 4A
State 4 to 5

This state will transition to a high-graded/grazed woodland idle phase with long term succession allowing woody species to become established and little to no grazing.

Transition 5C
State 5 to 2

This state will transition to a managed forest state with even-aged management, forest stand improvement, and suppression of grazing.

Transition 5B
State 5 to 3

This state will transition to a managed forest state with selective timber harvesting, forest stand improvement, and suppression of grazing.

Transition 5A
State 5 to 4

This state will transition to a grassland state with clearing, pasture planting, and grassland managment.