Name:
Pinus (echinata, taeda) - Quercus (incana, margarettiae, arkansana) Forest Alliance
Reference:
Southeastern Ecology Working Gro...
Description:
This alliance includes communities dominated by some combination of Pinus echinata and/or Pinus taeda, with the scrubby oaks Quercus incana, Quercus margarettiae, and/or Quercus arkansana. Quercus incana is the most characteristic and typically dominant of these. Stands of this alliance occur on xeric, sandy sites in the Coastal Plain west of the Mississippi River in eastern Texas, southeastern Oklahoma, northwestern Louisiana, and southwestern Arkansas.. The canopy coverage may be variable, reflecting the range of situations involved, ranging from open canopied woodlands on very well-drained Pleistocene terraces and low, broad ridges on deep, acidic sandy soils to slightly more-or-less dense examples on similarly droughty sites. Some stands are in effect short-statured, deciduous woodlands, but these are placed in this mixed forest alliance as well. In addition to the nominal canopy species, Carya texana may be present. Among the subcanopy, Quercus incana is arguably the most constant species. In most cases a patchy shrub stratum (varying from approximately 30-60% in total cover) consisting of stunted, scrubby Quercus spp. and tall shrubs ranging from 2.5-5 m in height is present. Quercus arkansana, a rare Coastal Plain endemic species, may occur in some examples. Due to xeric conditions, graminoids and forbs are very sparse in this community, and patches of exposed sand are common. Lichens (Cladonia spp.) and spike-moss (Selaginella arenicola ssp. riddellii) form large patches. Typical shrubs include Sassafras albidum, Vaccinium arboreum, Ilex vomitoria, Sideroxylon lanuginosum ssp. lanuginosum, Asimina parviflora, Chionanthus virginicus, Stillingia sylvatica, and Frangula caroliniana, and seedlings of canopy species. Depending, in part, upon management history, the herbaceous layer density may vary widely and is sometimes quite sparse. However, in nearly all cases it will contain a suite of habitat fidels, several of which are either endemic or nearly so to the West Gulf Coastal Plain. Herbaceous species may include Aristida desmantha, Schizachyrium scoparium, Opuntia humifusa, Cnidoscolus texanus, Eriogonum longifolium, Eriogonum multiflorum, Penstemon murrayanus, Polanisia erosa, Polygonella americana, Polygonella polygama, and Zornia bracteata. More open examples that approach woodland structure may contain scattered patches of fruticose lichens (Cladonia spp.) and possibly spike-moss (Selaginella arenicola ssp. riddellii). The historical fire frequency of these vegetation types is unknown but is widely believed to have been less than that of Pinus palustris-dominated woodlands (which sometimes occur adjacent to this type). Too frequent fires would not allow for the persistence of Pinus echinata and hardwood species, although young Pinus echinata has the ability to resprout when top-killed by fire. In some areas of eastern Texas these xeric sandhills occupy very limited portions of the landscape possibly suggesting that natural fire frequencies may not have been as constant or as frequent as would be necessary to maintain herbaceous-dominated woodlands. In addition, the extremely droughty soils contribute to only sparse fine fuel build-up making frequent, natural fires difficult to either ignite or spread. In the continued absence of fire, these mixed forests may become increasingly invaded by Pinus taeda. This alliance occurs on ridgetops and flat xeric uplands on very well-drained, acidic sandy soils in the West Gulf Coastal Plain and Upper West Gulf Coastal Plain of Arkansas, Louisiana, Oklahoma, and Texas. Its status in the western part of the East Gulf Coastal Plain is unclear.
Accession Code:
VB.CC.18351.PINUSECHINATATA
Plot-observations of this Community Concept:
0
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- status: accepted
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This Community's Level:
Alliance
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 This Community's Children:
[none]
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Names:
Scientific: Pinus (echinata, taeda) - Quercus (incana, margarettiae, arkansana) Forest Alliance
Translated: (Shortleaf Pine, Loblolly Pine) - (Bluejack Oak, Sand Post Oak, Arkansas Oak) Forest Alliance
UID: HIGHER_CLASS_UNIT.2.124946
NatureServe
Explorer
Code: A.386
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