Vegetational areas were developed primarily as a basis for recording the general distribution of plants and distinguishing the major vegetation types on the 169,000,000 acres of Texas. These areas are based on topographic, climatic and soil factors.

Ten areas are presented as the divisions of the vegetational types, based on the present working knowledge of the native flora. The most complex pattern of plant association occurs in the north-central portion of the State where the vegetation of the Land Resource Areas of the Grand Prairie, the East and West Cross Timbers and the North Central Prairies intermingle.

Generally, the boundaries between the vegetational areas are definite enough that the traveler can determine easily when leaving and entering each area. The dominant vegetation for each area is based on grass, but trees and other plants also help determine the vegetational areas. A brief summary of the characteristics of the 10 vegetational areas follows:

1. Pineywoods
This area contains approximately 16,000,000 acres of mixed pine-hardwood forest, growing on slightly acid, grayish-colored sand and sandy loam soils. The commercial soft timber species are loblolly, longleaf, shortleaf and slash pine. The hardwood timber species are oak, gum and hickory. The area is interspersed with native and improved grasslands, with cattle the primary grazing animals. Deer and quail are abundant in properly managed localities. The primary forage plants with proper grazing management include species of the bluestems, panicums, paspalums, blackseed needlegrass, Canada and Virginia wildrye, purpletop, broad, leaf and spike uniolas, switchcane, lovegrasses, Indiangrass and legume species.

The pineywoods area now has an understory and overstory of undesirable woody plants that are suppressing the growth of pine and desirable forage grasses. The primary forage grasses have been reduced and the grasslands invaded by threeawns, annual grasses, weeds, broomsedge bluestem, red lovegrass and shrubby woody species. The area can be improved in range condition by carrying out a well-balanced forage program of native and improved grasses with proper control of the undesirable woody plants.

2. Gulf Prairies and Marshes
This area comprises approximately 9,500,000 acres of Gulf Prairies and 500,000 acres of Gulf Marshes along the Texas coast, The soils of the Marshes are sandy loams and clays, while clay and clay loam soils exist in the Gulf Prairies. Much of the Gulf Prairies is fertile farmland. The area is well suited for cattle production. A well-balanced forage program can be carried out, making beef cattle productiofi profitable. The principal grasses of the prairies are tall bunchgrass, including big bluestem, little bluestem, seacoast bluestem, Indiangrass, eastern gama- grass, switchgrass and gulf cordgrass. Seashore saltgrass is frequent on moist saline sites. Grazing pressures have changed the composition of the range vegetation so that the grasses now existing are broomsedge bluestem, smutgrass, threeawns, tumblegrass and many other inferior grasses. The other plants that have invaded the productive grasslands are oak underbrush, macartney rose, huisache, mesquite, pricklypear, ragweed, bitter sneezeweed, broomweed and many other unpala- table annual weeds.

The vegetation of the Gulf Marshes consists primarily of sedges, bullrush, flat-sedges, beakrush, rtishes, marshhay cordgrass, marsh millet and maintencane. The marshes are grazed more satisfactorily during winter.

3. Post Oak Savannah
This area contains approximately 9,000,000 acres. The original vegetation was basically an oak and grassland savannah. Because of intensive grazing practices, much of this arca has degenerated to dense stands of a woody understory of yaupon, greenbriar and oak brush. Mesquite has become a serious problem on some range sites. The upland soils are sandy and sandy loam, while the bottomlands are sandy loams and clays.

The original vegetation consists mainly of little bluestem, Indiangrass, switchgrass, purpletop, silver bluestern, Texas wintergrass, spike uniola, longleaf uniola, post oak and blackjack oak. The area is still in native or improved grasslands with small farms located throughout.

The area now has a serious brush problem, and good forage plants were replaced by inferior plants of splitbeard bluestem, red lovegrass, broomsedge bluestem, broomweed, bullnettle and western ragweed.

A well-planned brush control program with proper stocking rates and grazing practices would restore the post oak savannah to high forage production.

4. Blackland Prairies
Area 4 contains approximately 11,500,000 acres with black clay-loam soils, developed under prairie grass-forb vegetation. For the most part, this fertile area has been brought under cultivation, and only small acreages of meadowland remain in original tall grass vegetation. In heavily grazed pastures, the tall bunchgrass has been replaced by buffalograss, Texas grama and other grasses of lower productivity. Mesquite, lotebush and other woody plants have invaded the productive grasslands.

The original grass vegetation includes little and big bulestenl Indiangrass, switchgrass, sideoats grama, hairy grama, tall dropseed, Texas wintergrass and buffalograss. The prairie forb vegetation is comprised largely of legumes and composites.

5. Cross Timbers and Prairies
Region 5 comprises approximately 16,500,000 acres of closely associated prairie and woodland sites. Sharp changes in the vegetational cover are associated with differences in soils and topography. The grass composition is rather uniform, even with the wide variation of sandy and clay soils.

The prairie-type grasses are little bluestem, big bluestem, Indiangrass, switchgrass, Canada wild- rye, sideoats grama, hairy grama, tall grama, tall dropseed, Texas wintergrass, blue grama and buffalograss. Mesquite, lotebush, juniper and other woody vegetation have increased greatly.

On the cross timber soils, the grasses are composed of big bluestem, little bluestem, hooded windmillgrass, sand lovegrass, Indiangrass, switchgrass and many species of legumes and forbs. The woody vegetation includes shinnery oak, blackjack oak, post oak and liveoak.

The entire area has been invaded heavily by woody brush plants of oak, mesquite, juniper and other unpalatable plants that furnish little forage for livestock.

A well-planned overall ranch program would restore the area to desirable forage production.

6. South Texas Plains
This region comprises approximately 20,000,000 acres of mostly level terrain but with diverse soil types and sites. The soils range from clays to sandy loams with a calcareous reaction. The original vegetation was comprised mainly of perennial warm-season bundigrass in post oak, live oak and mesquite savannahs. Other brush species formed dense thickets on the ridges and along streams. Long-continued grazing has altered the vegetation so that now the region is known as the "brush country." Most of the desirable grasses have persisted under the protection of brush and cacti.

There are distinct differences in the original plant communities on various range sites. The dominant grasses on the sandy loam soils are seacoast bluestem, bristlegrass, paspalum, windmiligrass, trichloris, silver bluestem, big sandbur and tanglehead. The dominant grasses on the clay and clay loams are silver bluestem, Arizona cottontop, buffalograss, curlymesquite, bristlegrass, pappusgrass, gramas, plains lovegrass, Texas cupgrass, vine-mesquite, other panicums and Texas wintergrass. Low saline areas are characterized by gulf cordgrass, seashore saltgrass, alkali sacaton and switchgrass. In the post oak and live oak savannahs, the grasses are mainly seacoast bluestem, Indiangrass, switchgrass, crinkleawn, paspaItims and panicums.

Buffelgrass and blue panicum are well-adapted to specific soil for seeding mechanically brush controlled acreages. Native grasses will reestablish on rangeland when competitive plants are reduced and a good range-livestock managment program is carried out.

7. Edwards Plateau
This area is the West Central Texas "Hill country" of some 24,000,000 acres. The Edwards Plateau is a region of limestone outcrops and rocky but fertile soil. In the east-central portion is the well marked "Central Basin" centering in Mason, Llano and Burnet counties, with a mixture of granitic and sandy soils. The western portion of the area is comprised of the semi-arid Stockton Plateau.

The soils are shallow, ranging from sands to clays and are calcareous in reaction. There is a wide variation of range sites.

This area is predominantly rangeland, with cultivation confined to the deeper soils. It contains a mixture of vegetation that makes the area suitable for combination stocking of cattle, sheep, goats and deer.

The principal grasses of the clay loam soils are cane bluestem, silver bluestem, little bluestem, sideoats grama, hairy grama, Indiangrass, curly mesquite, buffalograss, fall witchgrass, plains lovegrass, wildrye and Texas wintergrass.

The rocky areas support tall or mid-grass with an overstory of live oak, shinnery oak, juniper and mesquite. The heavy clay soils have a mixture of tobosagrass, buffalograss, sideoats grania and mesquite.

Throughout the Edwards Plateau, live oak, shinnery oak, mesquite and juniper dominate the woody vegetation. WoGdy plants have invaded to the degree that they should be controlled before range forage plants can re-establish. As one kind of brush species is controlled, another kind will invade the acreage. A combination of stocking rates with the proper grazing system would improve range condition and increase livestock production.

8. Rolling Plains
This area has approximately 24,000,000 acres of rolling-to-rough topography and mixed grassland vegetation. Soils range from coarse sands along outwash terraces adjacent to streams to tight or compact clays on redbed clays and shales. Rough broken lands on steep slopes are found in the western portion. About two-thirds of the area is rangeland even though cultivation is important in certain localities.

The original vegetation included little, big, sand and silver bluestem, Texas wintergrass, Indiangrass, switchgrass, si(teoats grama, blue grama, wildrye, tobosagrass and buffalograss on the clay Soils.

The sandy soils support the tall bunchgrass, with sand shinnery oak, sand sagebrush and mesquite the dominant woody plants.

Continued heavy grazing allows woody plants to increase and also the low order grasses of red grama, red lovegrass, tumblegrass, gummy lovegrass, Texas grama, sand dropseed and sandburs. The weeds that increase are western ragweed, croton and many others. Yucca is a problem plant on certain range sites.

Brush control coupled with a good grazing system wolild restore the native grassland to high production.

9. High Plains
Area 9 contains approximately 20,000,000 acres of level-to-slightly rolling plains with highly fertile clay and sandy soils. A large part of this area is under irrigated farming, but native grassland remains in about one-half of the High Plains.

Blue graina and buffalograss comprise the principal vegetation on the clay and clay loam sites. Other important grasses are little bluestem, western wheatgrass, Indiangrass, switchgrass and sand reedgrass on the sandy loam soils. Sand shinnery oak, sand sagebrush, mesquite and yucca are conspicuous invading brushy plants.

10. Trans-Pecos, Mountains and Basins
This area of approximately 18,000,000 acres includes most of the region west of the Pecos River. It is made up mainly of and valleys, plateaus and mountains. The soils are varied from sands to clays. There are some ferlile irrigated sections along the valleys. The vegetation is varied and can he divided into several types, such as creosote-tarbush, desert shrub, grama grassland, yucca and juniper savannahs, pine-oak forest and saline flats.

The mountains are 3,000 to 8,000 feet in elevation and support pinion pine, ponderosa pine and other forest vegetation on a few of the higher slopes.

The grass vegetation, especially on the higher mountain slopes, inculdes many southwestern and Rocky Mountain species not present elsewhere in Texas. On the desert flats, black grama, burrograss and fluffgrass are frequent. More productive sites have numerous species of grama, muhly, Arizona cotton top, dropseed and perennial threeawn grasses. At the higher elevations, plains bris- tlegrass, little bluestem, Texas bluestem, sideoats grama, chino grama, blue grama, pinon rice. grass, wolftail and several species of needlegrass are frequent.

The common invaders on all range sites are woody plants, burrograss, fluffgrass, hairy tridens, ear muhly, sand muhly, red grama, broom snake weed, croton, cacti and several poisonous plants.

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Authors: G.O. Hoffman, J. Daniel Rogers, R.J. Ragsdale, Roy V. Miller
Created: August 15, 1996
Updated: August 27, 1996