Piedmont Riverine Sandhills

Description

This mature forest state is generally dominated by a mixture of dry-site oaks and pines, with acid-tolerant flora in the understory.

Characteristics and indicators

Stands are uneven-aged with at least some old trees present.

Submodel

Description

This state develops in the immediate aftermath of agricultural abandonment, clearcut logging, or other large-scale disturbances that lead to canopy removal. Which species colonize a particular location in the wake of a disturbance does involve a considerable degree of chance. It also depends a great deal on the type, duration, and magnitude of the disturbance event.

Characteristics and indicators

Plant age distribution is even. Plants exhibit pioneering traits such as rapid growth, early reproduction, and shade-intolerance.

Submodel

Description

This state develops as a consequence of high-grading, where the most valuable trees are removed, leaving less desirable timber specimens behind. Trees left behind include undesirable timber species, trees of poor form, diseased trees, or genetically inferior trees.

Characteristics and indicators

Typically, high-graded stands consist of a combination of residual stems from the previous stand, a high proportion of undesirable shade-tolerant species, along with some regrowth from desirable timber species. In some cases, large-diameter trees of desirable timber species may be present, but upon closer inspection, these trees usually have serious defects that resulted in their being left behind in earlier cuts.

Resilience management

Landowners with high-graded stands have two options for improving timber production: 1) rehabilitate, or 2) regenerate. To rehabilitate a stand, the landowner must evaluate existing trees to determine if rehabilitation is justified. If the proportion of high-quality specimens present in the stand is low, then the stand should be regenerated. In many cases, poor quality of the existing stand is the result of decades of mismanagement. Drastic measures are often required to get the stand back into good timber production.

Dominant plant species

1. blackgum (Nyssa sylvatica), tree

2. sassafras (Sassafras albidum), tree

3. common persimmon (Diospyros virginiana), tree

4. oak (Quercus), tree

5. loblolly pine (Pinus taeda), tree

Submodel

Description

This converted state is dominated by planted timber trees. Loblolly pine (Pinus taeda) is the most commonly planted species. Even-aged management is the most common timber management system.

Note: if the user wishes to convert stands dominated by hardwoods to planted pine, clearcutting will usually be necessary first, allowing herbaceous pioneers to establish on the site in the weeks or months prior to planting. Users should utilize measures described in transition T2B under these circumstances.

Resilience management

Hardwood Encroachment:
Hardwood encroachment can be problematic in managed pine plantations. Good site preparation, proper stocking, and periodic thinning are advisable to reduce hardwood competition.

Overstocking:
The overstocked condition commonly occurs in naturally regenerated stands. When competition from other pines begins to impact the health and productivity of the stand, precommercial thinning should be considered. At this point, the benefit of thinning usually outweighs the potential for invasion and competition from non-pine species. As the target window for thinning passes, the condition of the stand can slowly deteriorate if no action is taken. Under long-term overstocked conditions, trees are more prone to stresses, including pine bark beetle infestation and damage from wind or ice.

High-grading:
In subsequent commercial thinnings, care should be taken in tree selection. High quality specimens should be left to reach maturity, while slower growing trees or those with defects should be removed sooner. If high quality specimens are harvested first, trees left behind are often structurally unsound, diseased, genetically inferior, or of poor form. This can have long-term implications for tree genetics and for the condition of the stand (Felix III 1983; Miller et al. 1995, 2003; Megalos 2019).

Dominant plant species

1. loblolly pine (Pinus taeda), tree

2. blackgum (Nyssa sylvatica), tree

3. sassafras (Sassafras albidum), tree

4. sweetgum (Liquidambar styraciflua), tree

5. oak (Quercus), tree

6. blueberry (Vaccinium), shrub

7. muscadine (Vitis rotundifolia), shrub

8. Japanese honeysuckle (Lonicera japonica), shrub

9. greenbrier (Smilax), shrub

10. blackberry (Rubus), shrub

11. St. Johnswort (Hypericum), shrub

12. rosette grass (Dichanthelium), grass

13. broomsedge bluestem (Andropogon virginicus), grass

14. longleaf woodoats (Chasmanthium sessiliflorum), grass

15. silver plumegrass (Saccharum alopecuroides), grass

16. sortbeard plumegrass (Saccharum brevibarbe var. contortum), grass

Submodel

Description

This converted state is dominated by herbaceous forage species.

Resilience management

Overgrazing and High Foot Traffic:
In areas that are subject to high foot traffic from livestock and equipment, and/or long-term overgrazing, unpalatable weedy species tend to invade, as most desirable forage species are less competitive under these conditions. High risk areas include locations where livestock congregate for water, shade, or feed, and in travel lanes, gates, and other areas of heavy use. Plant species that are indicative of overgrazing or excessive foot traffic on this ecological site include buttercup (Ranunculus spp.), plantain (Plantago spp.), curly dock (Rumex crispus), sneezeweed (Helenium amarum), cudweed (Pseudognaphalium spp.), slender yellow woodsorrel (Oxalis dillenii), Carolina horsenettle (Solanum carolinense), Virginia pepperweed (Lepidium virginicum), black medick (Medicago lupulina), Japanese clover (Kummerowia striata), annual bluegrass (Poa annua), poverty rush (Juncus tenuis), rattail fescue (Vulpia myuros), and Indian goosegrass (Eleusine indica), among others. A handful of desirable forage species are also tolerant of heavy grazing and high foot traffic, including white clover (Trifolium repens), dallisgrass (Paspalum dilatatum), and bermudagrass (Cynodon dactylon). An overabundance of these species, along with poor plant vigor and areas of bare soil, may imply that excessive foot traffic and/or overgrazing is a concern, either in the present or in the recent past.

Soil Fertility and pH Management:
Like overgrazing and excessive foot traffic, inadequate soil fertility and pH management can lead to invasion from several common weeds of pastures and hayfields. Species indicative of poor soil fertility and/or suboptimal pH on this ecological site include broomsedge bluestem (Andropogon virginicus), sweet vernalgrass (Anthoxanthum odoratum), dogfennel (Eupatorium capillifolium), Japanese clover (Kummerowia striata), common sheep sorrel (Rumex acetosella), and Carolina horsenettle (Solanum carolinense), among others. Most of these weedy invaders do not compete well in dense, rapidly growing pastures and hayfields. By maintaining soil fertility and pH, managing grazing to favor desirable forage species, and clipping behind grazing rotations when needed, forage grasses and forbs can usually outcompete weedy invaders.

Brush Encroachment:
Brush encroachment can be problematic in some pastures, particularly near fence lines where there is often a ready seed source. Pastures subject to low stocking density and long-duration grazing rotations can also be susceptible to encroachment from woody plants. Shorter grazing rotations of higher stocking density can help alleviate pressure from shrubs and vines with low palatability or thorny stems. Clipping behind grazing rotations, annual brush hogging, and multispecies grazing systems (cattle with or followed by goats) can also be helpful. Common woody invaders of pasture on this ecological site include rose (Rosa spp.), blackberry (Rubus spp.), saw greenbrier (Smilax bona-nox), Japanese honeysuckle (Lonicera japonica), common persimmon (Diospyros virginiana), eastern redcedar (Juniperus virginiana), black cherry (Prunus serotina), and Chinese privet (Ligustrum sinense).

Dominant plant species

1. Bermudagrass (Cynodon dactylon), grass

2. dallisgrass (Paspalum dilatatum), grass

3. bahiagrass (Paspalum notatum), grass

4. Johnsongrass (Sorghum halepense), grass

5. hairy crabgrass (Digitaria sanguinalis), grass

6. common carpetgrass (Axonopus fissifolius), grass

7. tall fescue (Schedonorus arundinaceus), grass

8. purpletop tridens (Tridens flavus), grass

9. broomsedge bluestem (Andropogon virginicus), grass

10. white clover (Trifolium repens), grass

11. narrowleaf plantain (Plantago lanceolata), grass

12. dogfennel (Eupatorium capillifolium), grass

13. field clover (Trifolium campestre), grass

14. black medick (Medicago lupulina), grass

15. Japanese clover (Kummerowia striata), grass

16. sericea lespedeza (Lespedeza cuneata), grass

Submodel

Description

This converted state produces food or fiber for human uses. It is dominated by domesticated crop species, along with typical weedy invaders of cropland. Soils associated with this ecological site are not well-suited to crop production. Erosion, plant water limitations, and soil fertility limitations can all be problematic on this ecological site when soils are put into crop production.

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