Isolated Situations

The loessial soils immediately east of the Mississippi River in western Tennessee and Mississippi, which produce high quality deciduous trees, deserve special attention. Severe erosion, aggravated by intensive cotton cultivation, encouraged the U.S. Congress in the 1940s to establish a reforestation program to reclaim these lands. The U.S. Forest Service's budget constraints in the early 1980s resulted in dismantling the program to reclaim these highly erosive lands and to manage them for wood production.

Figure 4.6 Kudzu, native to the Orient. Along with Japanese honeysuckle, also an exotic, this vine was introduced to check erosion. Here, a canyon-size gully was planted to the leguminous climber. Unfortunately, when these vines cover the land, as in this photo, they do not control erosion; they only hide it. Grazing cattle and browsing deer have also broken legs when falling into stump holes or washouts hidden by the vegetation. The practice has been largely eliminated, but escapes of the vines continue as a serious nuisance invader.

Figure 4.6 Kudzu, native to the Orient. Along with Japanese honeysuckle, also an exotic, this vine was introduced to check erosion. Here, a canyon-size gully was planted to the leguminous climber. Unfortunately, when these vines cover the land, as in this photo, they do not control erosion; they only hide it. Grazing cattle and browsing deer have also broken legs when falling into stump holes or washouts hidden by the vegetation. The practice has been largely eliminated, but escapes of the vines continue as a serious nuisance invader.

Once the soils are stabilized, cherrybark red oak, Shumard oak, black walnut, white ash, eastern cottonwood, and yellow-poplar grow so rapidly that radial increment often exceeds one-half inch per year. Here, too, sassafras grows sawlog-size stems 30 inches in diameter that produce three commercial 16-foot sawlogs. Cottonwood boles in the coves exceed 30 inches dbh and five merchantable logs in 30 years.

Figure 4.7 Southern red oaks in a relatively pure stand in the Southern Appalachians. A high-quality tree for furniture and paneling manufacture, it maintains itself as a permanent component of the climax forest. (USDA Forest Service photo by P. Carter, 1935)

Where the mantle thins to less than two feet, loblolly or shortleaf pines may occur naturally in mixture with hardwoods of poorer form. Also, large areas of abandoned cropland have been planted to loblolly pine.

While kudzu and to a lesser extent honeysuckle intrude into forest land throughout the South, the problem is most serious in these bluffs. Once looked upon as miracle plants that promised to revolutionize farm practices, the propensity of these vines, introduced from the Orient, for taking over land concerns forest managers. The kudzu weed, once thought to be especially useful for cattle forage and for erosion control, climbs fences, crosses ditches, and even engulfs houses and barns.

Parts of central Kentucky and Tennessee are characterized by soil of calcareous origin that excludes pine types. Oaks and hickories compose most of the natural broadleaf forest there, with other species occurring because of the effects of local topography. These woodlands serve as transitional vegetation between the mixed mesophytic forest of the Southern Appalachian Mountains to the east and the drier prairies to the west. Eastern redcedar, as a pioneer species in ecological succession, often precedes the appearance of deciduous trees in these areas.

The Post Oak belt and the East and West Cross Timber regions of Texas offer similar transitional situations, in these cases bridging the pine and hardwood forests growing on the red clay hills and brown sandy loams of East Texas and the fingers of low-pH soils that break up zones of the rich, black, calcareous high-pH clays to the west. (These blacklands, never covered with forest and now too valuable agriculturally to be retained in grass, usually produce soy beans and cotton.) Blackjack oak joins post oak in the cross-timbers, continuing to cover the xeric sandy land as coppice-reproduced woodlands. Mesquite, the cattle-carried invader from the Rio Grande to the south, competes with the scrubby trees and herbaceous plants that occur naturally on this land.10

Figure 4.8 Live oak accompanies post oak and junipers in the Texas "tension zone." Ball moss (insert), a parasite of the pineapple family (some may call it a saprophyte) grows on branches of oaks and other broadleaf species.
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