АҚШ-тың қызыл қоныс ормандарының экологиялық аймағы

Temperate coniferous forests ecoregion of the United States
the Piney Woods ecoregion in Arkansas, Louisiana, Oklahoma, and Texas

The Piney Woods cover a 54400 square miles (140,895 km2) area of eastern Texas, northwestern Louisiana, southwestern Arkansas and the southeastern corner of Oklahoma. American wisteria, a vine, may cover groves of trees. Two varieties of wetlands are common in the Piney Woods: bayous are generally found near rivers and sloughs are generally found near creeks. In bayous bald cypress, Spanish moss, and water lilies are common plants. Sloughs are shallow pools of standing water that most trees are not capable of growing in. Other species, such as the purple bladderwort, a small carnivorous plant, have found niches in sloughs. A baygall is another type of wetland found the Piney Woods and other forest of the Gulf Coast states in the USA. Hardy species of prickly pear cactus and yucca can be found in the forests where deep sands occur.

Within the U. S. Environmental Protection Agency's ecoregions scheme, the Piney Woods are known as the South Central Plains, a Level III ecoregion. Within the South Central Plains, eight Level IV ecoregions are identified: Tertiary Uplands, Floodplains and Low Terraces, Pleistocene Fluvial Terraces, Cretaceous Dissected Uplands, Southern Tertiary Uplands, Flatwoods, Red River Bottomlands, and Blackland Prairie.

The rolling Tertiary Uplands, gently to moderately sloping, cover a large area in eastern Texas, southern Arkansas, and northern Louisiana. The rolling Tertiary Uplands are dominated by commercial pine plantations that have replaced the native oak– hickory–pine forest. Ecoregion 35a is underlain by poorly consolidated Tertiary sand, silt, and gravel; it lacks the Cretaceous, often calcareous rocks of the Creataceous Dissected Uplands (35d) and the extensive Quaternary alluvium of Ecoregions 35b, 35g, and 73 (Mississippi Alluvial Plain). Soils areloamy, well drained, thermic Ultisols or moderately drained Alfisols, typically with sandy and loamy surface textures. The landscape is dissected by numerous small streams. Potential natural vegetation is southern floodplain forest as in the Mississippi Alluvial Plain (ecoregion 73); it is unlike the oak–hickory–pine forest of the higher, better drained, and lithologically distinct Tertiary Uplands (35a) and Cretaceous Dissected Uplands (35d). Settlements include (in Arkansas) Arkadelphia; Hope; Lockesburg; (in Oklahoma) Hugo; Bennington; and Caney. Protected areas include Crater of Diamonds State Park, some portions of Ouachita National Forest, and Boggy Depot Park.

The Southern Tertiary Uplands ecoregion of Texas and Louisiana generally covers the remainder of longleaf pine range north of the Flatwoods (35f) on Tertiary sediments. The preserve contains ten distinct ecosystems according to the National Park Service. Big Thicket National Preserve is one of two UNESCO Biosphere Reserves in Texas. The preserve has also been listed as a Globally Important Bird Area by the American Bird Conservancy. The preserve was established in 1974 under 16 U. S. Code § 698 Big Thicket National Preserve " to assure the preservation, conservation, and protection of the natural, scenic, and recreational values of a significant portion of the Big Thicket area in the State of Texas " Since the preserve's inception, the Conservation Fund has helped to increase the amount of protected acreage by .

The Piney Woods Region of the four state area is a noted area for Bigfoot (Sasquatch) sightings; with many legends dating back to pre European settlement. One such noted legend is the story of the Fouke Monster of Southern Arkansas; documented in the 1972 film The Legend of Boggy Creek. The area according to references lists this area to be the third highest in North America for these such sightings. Melanistic (black) cougars, another probable cryptid, have been noted by residents.