East-Central Texas Plains Post Oak Savanna and Woodland

Quercus fusiformis (plateau live oak) or Quercus virginiana (coastal live oak) may dominate sites within the Post Oak Savanna. Quercus stellata (post oak) may be present in these woodlands, but typically only as a minor component of the canopy, or it may be completely absent. These occurrences become more common and may occupy large areas in the southeastern part of this region, but occur elsewhere as well. In the western portion of the Post Oak Savanna, occurrences tend to occupy Claypan Savannah and Claypan Prairie ecoclasses, though this cover type is less common than others within these soil types. Ilex vomitoria (yaupon), Callicarpa americana (American beautyberry), Smilax bona-nox (saw greenbrier), Sideroxylon lanuginosum (gum bumelia), Toxicodendron radicans (poison ivy), Vitis mustangensis (mustang grape), Diospyros texana (Texas persimmon), and Zanthoxylum clava-herculis (Hercules' club) may be present in the shrub layer. To the south, Acacia rigidula (blackbrush), Colubrina texensis (Texas hogplum), Eysenhardtia texana (Texas kidneywood), Forestiera angustifolia (desert olive), and Zanthoxylum fagara (colima) may form a conspicuous shrub layer. Schizachyrium scoparium (little bluestem), Bothriochloa laguroides ssp. torreyana (silver bluestem), and Nassella leucotricha (Texas wintergrass) are among the many species of grass that may be present in the herbaceous layer, though many sites may have Bothriochloa ischaemum var. songarica (King Ranch bluestem), Paspalum notatum (bahiagrass), or Cynodon dactylon (bermudagrass) as herbaceous dominants.

Distribution Map

Photos

Public Land Occurrence

• Armand Bayou Nature Center
• Bastrop State Park: Texas Parks & Wildlife Department
• Lake Texana : Lavaca-Navidad River Authority
• Lavon Lake Recreation Area: US Army Corps of Engineers
• McKinney Roughs: Lower Colorado River Authority
• Memorial Park Conservancy: City of Houston
• Palmetto State Park: Texas Parks & Wildlife Department

Occurrences of this woodland are dominated by Quercus stellata (post oak) and/or Quercus fusiformis (plateau live oak), with Juniperus virginiana (eastern redcedar) as either a co-dominant of the overstory or as a conspicuous dominant of the shrub layer. This vegetation type is particularly well-represented on disturbed sites, particularly where fire is excluded. Dynamics described in Ecological Site Descriptions for Claypan Savannah, Sandy Loam, and Sandy sites in the Post Oak Savanna include this vegetation type in the Oak Scrub- Shrubland Community or the Post Oak - Elm Woodland Community. These communities result from the lack of fire and the presence of heavy continuous grazing. This vegetation type may sometimes be incorrectly mapped as Post Oak / Yaupon Motte and Woodland. The shrub layer may be dominated by Juniperus virginiana (eastern redcedar), but Ilex vomitoria (yaupon) may also be conspicuous. The herbaceous layer is often poorly developed, due to the closed nature of the canopy, resulting in the reduced potential for the development of fine fuels and the consequent maintenance of the redcedar dominance through lack of fire. Pinus taeda (loblolly pine) may be in the overstory near the Bastrop Lost Pines ecoregion.

Distribution Map

Photos

Public Land Occurrence

• Caddo National Grasslands, Lake Fannin: US Forest Service
• Caddo National Grasslands Wildlife Management Area: Texas Parks & Wildlife Department
• Gus Engeling Wildlife Management Area: Texas Parks & Wildlife Department

This mixed woodland type is typically dominated by Quercus fusiformis (plateau live oak) and Quercus stellata (post oak). Prosopis glandulosa (honey mesquite), Celtis laevigata (sugar hackberry), and Ulmus crassifolia (cedar elm) are also commonly encountered in the overstory. Ilex vomitoria (yaupon), Callicarpa americana (American beautyberry), Prosopis glandulosa (honey mesquite), and Acacia farnesiana (huisache) are commonly encountered in the shrub layer. Southern occurrences may have species such as Condalia hookeri (brasil), Diospyros texana (Texas persimmon), and Opuntia engelmannii var. lindheimeri (Lindheimer pricklypear) as significant components of the shrub layer. Herbaceous cover is typically low.

Distribution Map

Photos

Public Land Occurrence

• Lake Texana Recreation Area: Lavaca-Navidad River Authority

This vegetation type generally represents the deciduous woodland component of the system. The typical occurrence is dominated by Quercus stellata (post oak), with Quercus marilandica (blackjack oak) and/or Quercus fusiformis (plateau live oak) (particularly in the south) also present. Carya texana (black hickory) may be a significant component of the overstory, particularly on deep sands. Depending on site history and edaphic conditions, other species may be present in the overstory or may be better represented as shrubs. Such species as Celtis laevigata (sugar hackberry), Prosopis glandulosa (honey mesquite), Quercus nigra (water oak), Diospyros virginiana (eastern persimmon), Juniperus virginiana (eastern redcedar), Ulmus alata (winged elm), and Ulmus crassifolia (cedar elm) are often overstory components, and are often stunted (< 12 m in height). The shrub layer includes species such as Callicarpa americana (American beautyberry), Ilex decidua (possumhaw), Ilex vomitoria (yaupon), Sideroxylon lanuginosum (gum bumelia), Smilax bona-nox (saw greenbrier), Symphoricarpos orbiculatus (coral-berry), Vaccinium arboreum (farkleberry), and Zanthoxylum clava-herculis (Hercules' club). Herbaceous components are often represented by components of the surrounding prairies, primarily Schizachyrium scoparium (little bluestem), but also Sorghastrum nutans (Indiangrass), Andropogon gerardii (big bluestem), and, to the south and east, Paspalum plicatulum (brownseed paspalum). Other grass species may include Bothriochloa laguroides ssp. torreyana (silver bluestem), Elymus canadensis (Canada wildrye), Panicum virgatum (switchgrass), Paspalum floridanum (Florida paspalum), Paspalum setaceum (thin paspalum), Sporobolus compositus (tall dropseed), and Tridens flavus (purpletop).

Distribution Map

Photos

Public Land Occurrence

• Bastrop State Park: Texas Parks & Wildlife Department
• Caddo National Grasslands - Bois D’Arc Unit: US Forest Service
• Caddo National Grasslands – Lake Fannin: US Forest Service
• Caddo National Grasslands Wildlife Management Area: Texas Parks & Wildlife Department
• Calaveras Lake Park: Texas Parks & Wildlife Department
• Fairfield Lake State Park: Texas Parks & Wildlife Department
• Fort Boggy State Park: Texas Parks & Wildlife Department
• Goliad State Park: Texas Parks & Wildlife Department
• Gus Engeling Wildlife Management Area: Texas Parks & Wildlife Department
• Lake Texana: Lavaca-Navidad River Authority
• Lavon Lake Recreation Area: US Army Corps of Engineers
• MO Neasloney Wildlife Management Area: Texas Parks & Wildlife Department
• McKinney Roughs: Lower Colorado River Authority
• Navarro Mills Lake Recreation Area: US Army Corps of Engineers
• Palmetto State Park: Texas Parks & Wildlife Department
• Pat Mayse Wildlife Management Area: Texas Parks & Wildlife Department
• Somerville Lake Recreation Area: US Army Corps of Engineers

Many occurrences of this common vegetation type may have an exceedingly dense shrub layer dominated by Ilex vomitoria (yaupon). Such occurrences are conspicuous and widespread where lack of fire and heavy continuous grazing have allowed this woody species to dominate. The overstory is dominated by Quercus stellata (post oak). Juniperus virginiana (eastern redcedar) or, in southern occurrences Quercus fusiformis (plateau live oak) may also be present. Dynamics described in Ecological Site Descriptions for Claypan Savannah, Sandy Loam, and Sandy sites in the Post Oak Savanna include this mapping system in the Oak Scrub-Shrubland Community. The dense shrub layer is generally dominated by Ilex vomitoria (yaupon), almost to the exclusion of other shrub species, and the closed shrub canopy limits the development of a significant herbaceous layer. Near the Bastrop Lost Pines region, Pinus taeda (loblolly pine) may be an important overstory tree.

Distribution Map

Photos

Public Land Occurrence

• Caddo National Grasslands – Lake Fannin: US Forest Service
• Fairfield Lake State Park: Texas Parks & Wildlife Department
• Fort Parker State Park: Texas Parks & Wildlife Department
• MO Neasloney Wildlife Management Area: Texas Parks & Wildlife Department
• McKinney Roughs: Lower Colorado River Authority
• Normangee City Park: City of Normangee
• Palmetto State Park: Texas Parks & Wildlife Department
• Somerville Lake Recreation Area: US Army Corps of Engineers
• South Shores Park: Lower Colorado River Authority

This vegetation type represents the herbaceous expression of the overall system, which is a mosaic of woody and herbaceous cover types as suggested by reference to a savanna. These grasslands are often dominated by mid- and tallgrass species often present in the understory of woody expressions of the system. Dominant species include Schizachyrium scoparium (little bluestem), Sorghastrum nutans (Indiangrass), and Panicum virgatum (switchgrass). Other grasses present include Andropogon gerardii (big bluestem), Bothriochloa laguroides ssp. torreyana (silver bluestem), Paspalum plicatulum (brownseed paspalum) (to the south), Nassella leucotricha (Texas wintergrass), and Sporobolus cryptandrus (sand dropseed). Nonnative grass species such as Bothriochloa ischaemum var. songarica (King Ranch bluestem), Paspalum notatum (bahiagrass), Panicum coloratum (kleingrass), Dichanthium annulatum (Kleberg bluestem), and Cynodon dactylon (Bermuda grass) may dominate some sites. These grasslands may be difficult to differentiate in areas of transition to Blackland Prairie or Coastal Prairie. Claypan Savannah and Claypan Prairie ecoclasses may support occurrences of this vegetation type, particularly where land management practices including prescribed fire and other forms of brush management are implemented.

Distribution Map

Photos

Public Land Occurrence

• Bastrop State Park: Texas Parks & Wildlife Department
• Caddo National Grasslands – Bois D’Arc Unit: US Forest Service
• Caddo National Grasslands – Lake Fannin: US Forest Service
• Caddo National Grasslands Wildlife Management Area: Texas Parks & Wildlife Department
• Calaveras Lake Park: Texas Parks & Wildlife Department
• Gus Engeling Wildlife Management Area: Texas Parks & Wildlife Department
• MO Neasloney Wildlife Management Area: Texas Parks & Wildlife Department
• McKinney Roughs: Lower Colorado River Authority
• Navarro Mills Lake Recreation Area: US Army Corps of Engineers
• Palmetto State Park: Texas Parks & Wildlife Department
• Pat Mayse Wildlife Management Area: Texas Parks & Wildlife Department
• Purtis Creek State Park: Texas Parks & Wildlife Department
• Somerville Lake Recreation Area: US Army Corps of Engineers

These evergreen shrublands often occur on sandy soils in the vicinity of live oak woodlands. They are dominated by the shrub form of Quercus fusiformis (plateau live oak, often referred to locally as running live oak) that may represent clones forming dense, more or less continuous, shrub canopy with occasional emergent live oaks. Some sites may also have other shrub species such as Ilex vomitoria (yaupon), Acacia rigidula (blackbrush), and/or Condalia hookeri (brasil). The closed shrub canopy limits the development of the herbaceous layer.

Distribution Map

Photos

Public Land Occurrence

• None.

Uncommon, relatively closed canopy woodland or forest on slopes greater than twenty percent and dominated by Juniperus virginiana (eastern redcedar). This type often occupies the Sandstone Hill ecoclass and is often associated with areas near the contact of the Reklaw Formation and the Carrizo Sand.

Distribution Map

Photos

Public Land Occurrence

• McKinney Roughs: Lower Colorado River Authority

Uncommon forest on slopes greater than twenty percent with the canopy co-dominated by oak species (such as Quercus stellata (post oak), Quercus marilandica (blackjack oak), and Quercus shumardii (Shumard oak)) and Juniperus virginiana (eastern redcedar). Ulmus crassifolia (cedar elm) may also be present to common in the canopy. This type occurs in areas near the Red River on soils of the Shallow and Sandy Loam ecoclasses in Grayson and Fannin counties, as well further south on various soils between Milam and Gonzales counties (in Phase I). Near the Bastrop Lost Pines region, Pinus taeda (loblolly pine) may be an important overstory species.

Distribution Map

Photos

Public Land Occurrence

• Caddo National Grasslands – Lake Fannin: US Forest Service
• Eisenhower State Park: Texas Parks & Wildlife Department
• McKinney Roughs: Lower Colorado River Authority
• Palmetto State Park: Texas Parks & Wildlife Department

This broad-leaved evergreen forest or woodland is mapped on slopes greater than 20% and is dominated by Quercus fusiformis (plateau live oak), though hardwood species may also occur in the canopy.

Distribution Map

Photos

Public Land Occurrence

• None.

This deciduous forest vegetation type is found on slopes greater than twenty percent along the Red River and its tributaries, as well as on slopes from Milam to Gonzales counties and elsewhere. Slopes on calcareous substrates along the Red River may be dominated by species such as Quercus muehlenbergii (chinkapin oak), Quercus shumardii (Shumard oak), Ulmus americana (American elm), and Ulmus crassifolia (cedar elm). In the south, slopes are generally not on calcareous substrate and Quercus muehlenbergii (chinkapin oak) is lacking. On these sites, slopes may be dominated by Quercus stellata (post oak), Ulmus crassifolia (cedar elm), Ulmus americana (American elm), Quercus marilandica (blackjack oak) and Celtis laevigata (sugar hackberry) and less commonly Quercus shumardii (Shumard oak). This vegetation type is poorly understood, and may be compositionally quite similar to surrounding woodlands. The greater topographic relief associated with this system results in more mesic conditions leading to the development of denser overstory canopy.

Distribution Map

Photos

Public Land Occurrence

• Caddo National Grasslands – Lake Fannin: US Forest Service
• Eisenhower State Park: Texas Parks & Wildlife Department
• Fort Boggy State Park: Texas Parks & Wildlife Department
• Fort Parker State Park: Texas Parks & Wildlife Department
• McKinney Roughs: Lower Colorado River Authority
• Monument Hill\Kreische Brewery State Historical Sites: Texas Parks & Wildlife Department
• Palmetto State Park: Texas Parks & Wildlife Department
• Pat Mayse Wildlife Management Area: Texas Parks & Wildlife Department
• Purtis Creek State Park: Texas Parks & Wildlife Department
• Somerville Lake Recreation Area: US Army Corps of Engineers

This woodland of mixed broad-leaved evergreen and deciduous overstory is dominated by Quercus stellata (post oak) and Quercus fusiformis (plateau live oak) and occupies slopes greater than 20%.

Distribution Map

Public Land Occurrence

• None.