Texas Almanac, 1990-1991 Page: 87
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ENVIRONMENT 87
Vegetational Areas
(Editor's Note: This article was updated for this edition of The Texas Almanac by Stephan L. Hatch, Curator,
S.M. Tracy Herbarium and Associate Professor, Dept. of Range Science, Texas A&M University.)Difference in amount and frequency of rainfall, in
soils and in frost-free days gives Texas a great variety
of vegetation. From the forests of East Texas to the de-
serts of West Texas, from the grassy plains of North
Texas to the semi-arid brushlands of South Texas, plant
species change continuously.
The following discussion of Texas' 10 vegetational
areas (see map) and rangeland resources was prepared
for the Texas Almanac by authorities at Texas A&M
University.
Sideoats grama, which occurs on more different soils
in Texas than any other native grass, was officially des-
ignated as the state grass of Texas by the Texas Legis-
lature in 1971.
The 10 principal plant life areas of Texas, starting in
the east, are:
1. Piney Woods. Most of this area of some 16 million
acres ranges from about 50 to 500 feet above sea level
and receives 40 to 60 inches of rain yearly. Many rivers,
creeks and bayous drain the region. Nearly all of Texas'
commercial timber comes from this area. Pine is the
principal timber. There are three native species - the
longleaf, shortleaf and loblolly pine. An introduced spe-
cies, the slash pine, also is widely grown. Hardwoods in-
clude a variety of oaks, elm, hickory, magnolia, sweet
and black gum, tupelo and others.
The area is interspersed with native and improved
grasslands. Cattle are the primary, grazing animals.
Deer and quail are abundant in properly managed lo-
calities. Primary forage plants, under proper grazing
management, include species of the bluestems, rossette.
grass, panicums, paspalums, blackseed needlegrass, Can-
ada and Virginia wildryes, purpletop, broadleaf and
spike woodoats, switchcane, lovegrasses, Indiangrass and
legume species.
Highly disturbed areas have understory and oversto-
ry of undesirable woody plants that suppress growth of
pine and desirable 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.
2. Gulf Prairies and Marshes. The gulf prairies and
marshes cover approximately 10 million acres. There
are two subunits: (a) The marsh and salt grasses imme-
diately at tidewater, and (b) a little farther inland, a
strip of bluestems and tall grasses, with some gramas in
the western part. These grasses, except salt and marsh
grasses, make excellent grazing. Oaks, elm and other
hardwoods grow to some extent, especially along
streams, and the area has some post oak and brushy ex-
tensions along its borders. Much of the Gulf Prairies is
fertile farmland. The area is well suited for cattle.
Principal grasses of the Gulf Prairies are tall bunch-
grasses, including big bluestem, little bluestem, seacoast
bluestem, Indiangrass, eastern gamagrass, Texas winter-
grass, switchgrass and gulf cordgrass. Seashore saltgrass
occurs on moist saline sites. Heavy grazing has changed
the range vegetation in many cases so that the predom-
inant grasses are the less desirable broomsedge blues-
tem, smutgrass, threeawns, tumblegrass and many other
inferior grasses. The other plants that have invaded the
productive grasslands include oak underbrush, Ma-
cartney rose, huisache, mesquite, prickly pear, ragweed,
bitter sneezeweed, broomweed and others.
Vegetation of the Gulf Marshes consists primarily of
sedges, bullrush, flat-sedges, beakrush and other rushes,
smooth cordgrass, marshhay cordgrass, marsh millet and
maidencane. The marshes are grazed best during win-
ter.
3. Post Oak Savannah. This secondary forest region,
also called the Post Oak Belt, covers some 9 million
acres. It is immediately west of the primary forest re-
gion, with less annual rainfall and a little higher eleva-
tion. Principal trees are post oak, blackjack oak and
elm. Along streams are growths of pecans, walnuts and
other kinds of water-demanding trees. The southwes-
tern extension of this belt is often poorly defined, with
large areas of prairie.
The upland soils are sandy and sandy loam, while the
bottomlands are sandy loams and clays.
The original vegetation consisted mainly of little
bluestem, big bluestem, Indiangrass, switchgrass, pur-
pletop, silver bluestem, Texas wintergrass, spike wood-
oats, longleaf woodoats, post oak and blackjack oak. The
area is still largely native or improved grasslands, withsmall farms located throughout. Intensive grazing has
caused much of this area to degenerate to dense stands
of a woody understory of yaupon, greenbriar and oak
brush. Mesquite has become a serious problem. Good
forage plants have been replaced by such inferior plan-
ts as splitbeard bluestem, red lovegrass, broomsedge
bluestem, broomweed, bullnettle and western ragweed.
4. Blackland Prairies. This area of about 11 million
acres, while called a "prairie," has much timber along
the streams, including a variety of oaks, pecan, elm,
horse-apple (bois d'arc) and mesquite. In its native state
it was largely a grassy plain - the first native grassland
in the westward extension of the Southern Forest Re-
gion.
Most of this fertile area has been cultivated, and
only small acreages of meadowland remain in original
vegetation. In heavily grazed pastures, the tall bunch-
grass has been replaced by buffalograss, Texas grama
and other less productive grasses. Mesquite, lotebush
and other woody plants have invaded the grasslands.
The original grass vegetation includes big and little
bluestem, Indiangrass, switchgrass, sideoats grama,
hairy grama, tall dropseed, Texas wintergrass and buffa-
lograss. Nongrass vegetation is largely legumes and
composites.
5. Cross Timbers and Prairies. Approximately 16.5
million acres of alternating woodlands, often called the-
West Cross Timbers, and prairies constitute this region.
Sharp changes in the vegetational cover are associated
with different soils and topography, but the grass com-
position is rather uniform.
The prairie-type grasses are big bluestem, little
bluestem, Indiangrass, switchgrass, Canada wildrye,
sideoats grama, hairy grama, tall grama, tall dropseed,
Texas wintergrass, blue grama and buffalograss.
On the Cross Timbers soils, the grasses are com-
posed of big bluestem, little bluestem, hooded windmill-
grass, sand lovegrass, Indiangrass, switchgrass and
many species of legumes. The woody vegetation includ-
es shinnery, blackjack, post and live oaks.
The entire area has been invaded heavily by woody
brush plants of oaks, mesquite, juniper and other unpal-
atable plants that furnish little forage for livestock.
6. South Texas Plains. South of San Antonio, between
the coast and the Rio Grande, are some 20 million acres
of subtropical dryland vegetation, consisting of small
trees, shrubs, cactus, weeds and grasses. The area is
noteworthy for extensive brushlands, known as the
brush country, or the Spanish equivalents of chaparral
or monte. Principal plants are mesquite, small live oak,
post oak, prickly pear (Opuntia) cactus, catclaw, black.
brush, whitebrush, huajillo, huisache, cenizo and others
which often grow very densely. The original vegetation
was mainly perennial warm-season bunchgrasses in post
oak, live oak and mesquite savannahs. Other brush spe-
cies form dense thickets on the ridges and along
streams. Long-continued grazing caused the region to
be densely covered with a mixture of brush. 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 soils. Dominant grasses on the
sandy loam soils are seacoast bluestem, bristlegrass,
paspalum, windmillgrass, trichloris, silver bluestem, big
sandbur and tanglehead. Dominant grasses on the clay
and clay loams are silver bluestem, Arizona cottontop,
buffalograss, common curlymesquite, bristlegrass,
pappusgrass, gramas, plains lovegrass, Texas cupgrass,
vinemesquite, 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,
paspalums and panicums. Today much of the area has
been reseeded to buffelgrass.
7. Edwards Plateau. These 24 million acres are rolling
to mountainous, with woodlands in the eastern part and
grassy prairies in the west. There is a good deal of bru-
shy growth in the central and eastern parts. The combi-
nation of grasses, weeds and small trees is ideal for
cattle, sheep, goats, deer and wild turkey.
This limestone-based area is characterized by the
large number of springfed, perennially flowing streams
which originate in its interior and flow across the Bal-
cones Escarpment, which bounds it on the south
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Kingston, Mike. Texas Almanac, 1990-1991, book, 1989; Dallas, Texas. (https://texashistory.unt.edu/ark:/67531/metapth162512/m1/89/: accessed May 8, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu; crediting Texas State Historical Association.