Loamy Rise, Moderately Wet
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Restoration pathway R2A More details
- Transition T2A More details
- Transition T2B More details
- Transition T3A More details
- Transition T3A More details
- Transition T3A More details
- Transition T4A More details
- Restoration pathway R5A More details
- Transition T5A More details
- Transition T7B More details
- Transition T7B More details
- Transition T6A More details
- Transition T7A More details
- Transition T7B More details
- Transition T7B More details
- Restoration pathway R7A More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
State 1
Longleaf /Wiregrass/Bluestem
Description
Plant community species composition and productivity data that follow were determined through on-site inventory at five locations that are representative of the reference community.
Transition pathways from one plant community phase to another within the reference state (state 1) are described below. These pathways describe managment practices associated with triggers and thresholds of these transitions.
Submodel
State 2
Mixed Hardwood/Pine Forest
Description
The mixed longleaf pine, hardwood forest state is characterized by a more closed canopy relative to the reference state. Hardwood trees such as post and blackjack oak, sweetgum and blackgum compete with the remaining longleaf for canopy space. Shrub density and mass is increased relative to the reference state. Herbaceous species richness and productivity will continue to decline with canopy closure and the resulting decrease in sunlight penetration.
Submodel
Description
Lack of a favorable environment for regeneration and competition from hardwoods and other pines has resulted in either longleaf being lost from the site, or remaining individual trees being widely dispersed. Canopy closure is 100%, and dominated by oaks, hickories and sweetgum. Because of lack of sunlight penetration to the understory, shrub size and numbers are reduced relative to state 2, and herbaceous species characteristic of the reference state are no longer present.
Submodel
Description
Longleaf pine are planted to grow trees to a marketable size, and in the interim sell pine straw as an urban landscape mulch, or to attempt to restore a system that would be similar to the reference plant community (Alig et al., 2002). However, the diversity and richness of herbaceous species and associated animals found in the reference state are unlikely to be achieved. Grasses commonly planted in this state are wiregrass, little bluestem, Indiangrass and switchgrass.
Submodel
Description
Loblolly and slash are the pine species most often planted in the area to produce a marketable wood product. Subsequent management will be in keeping with long-term and interim objectives and may include vegetation management with prescribed burning, and periodic stand thinning.
Submodel
Description
If a pine plantation is not established, the most common agricultural use of the site is pasture or hay production. Fruit and vegetable production, and row crops can be regionally important.
Submodel
Mechanism
Triggers – Decrease in Fire Frequency.
When fire is removed from the system for more than five years, the site may begin transitioning to a mixed pine/hardwood forest state. Frequent, low-intensity fire is the dominant natural ecological force. Absence of fire beyond the natural range of return intervals (2-3 years) results in both rapid and long term changes of vegetation. Communities will show evidence of change after only a few years (3) without fire. Encroachment by hardwood trees and other pines is reversible for several years, but eventually becomes irreversible without persistent management and costly methods (Walker and Silletti, 2006).
Using dormant season burns exclusively will reduce wiregrass. This results in reduction of fine fuels, lowering fire intensity potentially allowing survival of hardwood species.
Exclusion of fire allows accumulation of litter which hinders longleaf pine germination as longleaf pine requires an exposed mineral soil free of surface litter for germination. In addition, due to competition seedlings will not elongate.
Threshold – With lack of fire, hardwood species exceed 3-inch basal diameter and fire mortality rates decline.
Mechanism
This restoration pathway is valid for a tract that transitioned to state 2 from state 1 only. It does not apply to areas that transitioned to state 2 from any other state (4).
Suitable restoration techniques depend on the degree of ecosystem degradation, including soil seed bank depletion.
Effective hardwood and mid-story shrub removal may be accomplished by mechanical means and use of selective herbicides. Removal of over story hardwoods significantly improves regeneration and growth of longleaf seedlings, and increases understory herbaceous vegetation.
Once sufficient fine fuels exist, a prescribed burn should be conducted (March to July). Burning August-September should be avoided to minimize mortality to young longleaf pine seedlings.
Once longleaf pine regeneration has been reestablished, and hardwood competition is minimal, a two-year dormant season burn will minimize fuel accumulation and should control mid story species. To expedite restoration to the reference plant community, periodic growing season burns should be included in the fire regime. Efforts to establish herbaceous understory species may need to be undertaken if soil seed bank is severely depleted.
Sites dominated by longleaf pine with native understory (Moderately degraded-R2A) -
Frequent growing-season fires are needed to adequately control competing woody plants on upland sites with better soils. As on flatwoods sites, frequent growing season fires over many years are required to reduce the hardwood rootstocks (Boyer, 1990a). As in other longleaf pine ecosystem types, a series of dormant-season fires may be necessary to gradually reduce fuel levels before growing season burning begins. Where wiregrass components are evident in the understory, selective herbicide application may be favored over mechanical reduction of non-merchantable woody species in readjusting species composition and dominance (Boyer, 1991).
Sites dominated by other species (Severely degraded-Closed Canopy)-
Repeated and prolonged treatment with prescribed fire should eventually reduce the abundance and cover of woody plants in the understory. It is probable that at least a portion of the native understory still exists in the soil seed bank or as suppressed individuals (Varner et. al., 2000). Therefore, restoration would begin with burning to reduce fuel and initiate control of woody shrubs and hardwoods. If timber harvest is not a practical option felling/girdling or herbicide may be used to reduce unwanted mid-story and overstory pine and hardwood trees. In summary, areas that are severely degraded may require growing season/dormant season annual fires, mechanical removal and herbicide treatment of an encroaching midstory and overstory pine and hardwood trees. To facilitate restoration, native plantings of desired species are recommended.
The time it takes to restore the reference plant community will depend in large part on the intensity of the restoration effort. Relatively aggressive approaches that include use of herbicides, mechanical removal of competing species, and replanting of desirable species can shorten the process. However, depending in part on the degree of site disturbance, restoration to the reference plant community may take 20 years or more after appropriate management has been implemented.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Burning |
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|
Tree/Shrub Establishment |
Mechanism
Triggers -
Persistence and increases in hardwood cover causes a decrease in herbaceous understory vegetation
Threshold –
100% canopy cover dominated by hardwoods and loss of longleaf pine from the state; loss of herbaceous understory species from the state, including seed bank depletion.
Mechanism
Clear cut. Mechanical and chemical control of remaining vegetation. Site prep (K-G blade, root rake, and disking) for grass and tree establishment. Plant native grasses and forbs. Plant longleaf pine spaced to allow grass establishment.
Mechanism
Clear cut. Mechanical and chemical control of remaining vegetation. Site preparation (K-G blade, root rake, and disking) for grass and tree establishment. Plant native grasses and forbs. Plant longleaf pine spaced to allow grass establishment.
Mechanism
Clear cut. Mechanical and chemical control of remaining vegetation. Site preparation (K-G blade, root rake, and disking) for tree establishment. Plant pines (slash or loblolly) at recommended rates.
Mechanism
Clear cut. Mechanical and chemical control of remaining vegetation. Site preparation (K-G blade, root rake, and disking) for pasture or crop establishment. Remove debris and stumps. Prepare seedbed and establish row crop or pasture species.
Mechanism
Triggers – Decrease in Fire Frequency.
When fire is removed from the site for more than five years the site may begin transitioning to a mixed pine / hardwood forest state. Frequent, low- intensity fire is the dominant natural ecological force. Absence of fire beyond the natural range of return intervals (2-3 years) results in both rapid and long term changes of vegetation. Communities will show evidence of change after only a few years (3) without fire. Encroachment by hardwood trees and other pines is reversible for several years, but eventually becomes irreversible without costly, persistent management.
Using dormant season burns exclusively will alter understory composition. Research has demonstrated that wiregrass produces seed only during years that the plant has been exposed to a growing season fire. Without reproduction and the subsequent regeneration of wiregrass, this important fine-fuels component of the system will eventually decrease. If this occurs, the resulting lower intensity fires are more likely to allow hardwood species to escape control.
Exclusion of fire allows an over-accumulation of litter which hinders longleaf pine germination because longleaf pine requires an exposed mineral soil free of surface litter for germination. In addition, due to competition longleaf seedlings will not elongate.
Threshold – With lack of fire, hardwood species exceed 3-inch basal diameter and fire mortality rates decline.
Mechanism
Selective thinning of trees, preferably to create .25 - .5 acre gaps. Mechanical or chemical control of any understory vegetation. Plant container-grown longleaf pine seedlings in the gaps. Plant native grasses, and if desired, native forbs. Begin prescribed burning every 2 to 3 years during the growing season as fine fuels are adequate to carry a fire.
The Longleaf Pine Ecosystem Restoration Project (LPER) describes how mono-culture pine plantations on select Georgia State Lands were restored to healthy longleaf pine-wiregrass ecosystems (Georgia Department of Natural Resources, 2007). The study sites in the project correspond to state 4 in the State and Transition Model.
Conversion of plantations is a multi-step restoration process that may involve aggressive application of adaptive management practices such as planting native vegetation and continued monitoring and management to ensure overall success. Though the table above shows lower longleaf pine survival than predicted, the overall project was successful in developing effective strategies for converting plantations to relatively diverse, multi-aged longleaf pine forests. These strategies include: initiating gradual canopy conversion through thinning to create small gaps, reducing hardwood encroachment through the use of prescribed fire and herbicide application, utilizing prescribed fire to restore native groundcover and promote fine fuels, and acquiring wiregrass seed from native stands through private landowner incentives.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Forest Stand Improvement |
Mechanism
Clear cut. Mechanical and chemical control of remaining vegetation. Site preparation (K-G blade, root rake, and disking) for grass and tree establishment. Plant native grasses and forbs. Plant longleaf pine spaced to allow grass establishment.
Mechanism
Mechanical and/or chemical control of existing vegetation. Site preparation (KG-blade, root rake, and/or disking) for tree establishment. If transitioning to state 5, plant pines (slash or loblolly) at recommended rates. If transitioning to state 4, plant native grasses. Plant longleaf pine spaced to allow grass establishment.
Mechanism
Mechanical and/or chemical control of existing vegetation. Site preparation (KG-blade, root rake, and disking) for tree establishment. Plant pines (slash or loblolly) at recommended rates.
Mechanism
Management ceases. Early successional species become established.
Mechanism
Lack of management that includes vegetation control, allowing pines and hardwoods to become established.
Mechanism
Mechanical and/or chemical control of existing vegetation. Site prep (KG-blade, root rake, and/or disking) for tree establishment. If transitioning to state 5, plant pines (slash or loblolly) at recommended rates. If transitioning to state 4, plant native grasses. Plant longleaf pines spaced to allow grass establishment.
Development of restoration techniques for upland sites once used for agriculture or intensive forestry has begun only recently. It is unlikely that many of the native understory grasses and forbs survived intensive soil disturbance; however, there is a large soil seed bank of herbaceous weeds that must be controlled. Annual herbicide application to control non-native weedy invasion such as Bermuda grass (Cynodon dactylon) may be necessary, prior to native plantings. Brush control may require mechanical as well as selective herbicide applications followed by the introduction of both dormant season and growing season fires over long periods of time. More information will be forthcoming as information becomes available.
Mechanism
Mechanical and/or chemical control of existing vegetation. Site prep (KG-blade, root rake, and/or disking) for tree establishment. If transitioning to state 5, plant pines (slash or loblolly) at recommended rates. If transitioning to state 4, plant native grasses. Plant longleaf pines spaced to allow grass establishment.
Development of restoration techniques for upland sites once used for agriculture or intensive forestry has begun only recently. It is unlikely that many of the native understory grasses and forbs survived intensive soil disturbance; however, there is a large soil seed bank of herbaceous weeds that must be controlled. Annual herbicide application to control non-native weedy invasion such as Bermuda grass (Cynodon dactylon) may be necessary, prior to native plantings. Brush control may require mechanical as well as selective herbicide applications followed by the introduction of both dormant season and growing season fires over long periods of time. More information will be forthcoming as information becomes available.
Mechanism
Chemical control of vegetation. Mechanical control where necessary for woody species. Tillage as necessary. Establish row crop or pasture species.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
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|
Prescribed Burning |
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Cover Crop |
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Forage and Biomass Planting |
Model keys
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