Southeastern Great Plains Riparian Forest

Geology

As defined, this system occupies buffer zones of headwater streams, and soils develop in place over a variety of geologic surfaces

Landform

Valleys and drainages along headwater streams of the Sulphur, Sabine, Navasota, Brazos, upper Trinity River, and middle portions of the Guadalupe and San Antonio River Basins. Typically in areas with erosional processes dominating over alluvial deposition. In the Trinity River basin, occurrences were mapped upstream of approximately the Leon/Madison County line, near the confluence with Cobb Creek.

Soils

By definition, this system is mapped along drainages upstream of the Bottomland Ecoclasses, so they will be mapped on soils of the surrounding uplands.

Parent Description

Trees that may be present in stands of this system include Celtis laevigata (sugar hackberry), Ulmus crassifolia (cedar elm), Platanus occidentalis (American sycamore), Populus deltoides (eastern cottonwood), Quercus fusiformis (plateau live oak), Quercus nigra (water oak), Quercus phellos (willow oak), Sapindus saponaria var. drummondii (western soapberry), Salix nigra (black willow), Fraxinus americana (white ash), Fraxinus pennsylvanica (green ash), Gleditsia triacanthos (common honeylocust), Prosopis glandulosa (honey mesquite), and Carya illinoinensis (pecan). To the east, Quercus falcata (southern red oak) and Liquidambar styraciflua (sweetgum) may become important components of the overstory. To the east, evergreen dominated occurrences may contain Pinus taeda (loblolly pine) or Pinus echinata (shortleaf pine), as well as Juniperus virginiana (eastern redcedar). The shrub layer development is variable, sometimes with species such as Amorpha fruticosa (indigobush), Forestiera acuminata (swamp privet), Ilex decidua (possumhaw), Ilex vomitoria (yaupon), Sideroxylon lanuginosum (gum bumelia), Juniperus virginiana (eastern redcedar), Diospyros virginiana (common persimmon), Cornus drummondii (roughleaf dogwood), Condalia hookeri (brasil), Acacia farnesiana (huisache), and/or Viburnum rufidulum (rusty blackhaw). A few sites may be shrub dominated without an overstory canopy, containing species such as Forestiera acuminata (swamp privet), Cephalanthus occidentalis (common buttonbush), Acacia farnesiana (huisache), or Sesbania drummondii (rattlebox sesbania). Herbaceous cover is also variable, depending on overstory and shrub canopies and recent flooding history. Herbaceous species may include Elymus virginicus (Virginia wildrye), Verbesina virginica (frostweed), Chasmanthium latifolium (creek oats), Chasmanthium sessiliflorum (narrowleaf woodoats), Tripsacum dactyloides (eastern gamagrass), Symphyotrichum drummondii var. texanum (Drummond's aster), Amphiachyris dracunculoides (common broomweed), Ambrosia psilostachya (western ragweed), Geum canadense (white avens), Sanicula canadensis (Canada snakeroot), Panicum virgatum (switchgrass), Galium spp. (bedstraw), and Carex spp. (sedges). Upland species such as Schizachyrium scoparium (little bluestem), Nassella leucotricha (Texas wintergrass), and Sorghastrum nutans (Indiangrass) may be common. Woody vines such as Smilax bona-nox (saw greenbrier), Toxicodendron radicans (poison ivy), Ampelopsis arborea (peppervine), and Vitis spp. (grapes) may be common. The environment and characteristics of the vegetation of this system become drier from east to west, with moister representatives (such as communities containing Quercus nigra (water oak)) occurring in the eastern parts of the range. Non-native grass species that may be common to dominant on these sites include Arundo donax (giant reed) and Cynodon dactylon (bermudagrass) and Sorghum halepense (Johnsongrass). The non-native species, such as Ligustrum spp. (privets) and Triadica sebifera (Chinese tallow), may be commonly encountered.