Oaks Hickories and their Deciduous

Upland hardwood types of the southern United States often intermingle with conifers to form mixed stands of broadleaf and needleleaf trees. Depending on soil, physiography, fire history, and past land use, pure deciduous forests occur over acreages of various sizes. Numerous oak species, several hickories, yellow-poplar, maples, sweetgum, American beech, sycamore, and several birches predominate. Found with these trees are about 100 other hardwood species, many of minor commercial value for particular uses.

Figure 4.1 Open-grown white oak. This large specimen in South Carolina, with a crown spread of 132 feet, provided shade for homes and seeds for animals to carry as they initiated new forests. (USDA Forest Service photo)

Figure 4.2 Osage-orange, the bois d'arc tree. Squirrels, deer, and birds eat the seeds after the compound fruit has fallen to the ground and the hard coat softened by fermentation. Natural stands arise from these seeds. As recently as World War II, a dye was extracted from the wood for khaki uniforms. "Apples" (inset) provided ballast on return trips for boats plying the Red River. Later these "apples" were replaced with goods for shipment, the unloaded fruit providing seeds for living fences far distant from the original narrow range of the species in north-central Texas. The very hard and durable wood, from trees bearing thorns so tough that they puncture truck tires, is harvested throughout the East for specialty products. (USDA Forest Service photo)

Figure 4.2 Osage-orange, the bois d'arc tree. Squirrels, deer, and birds eat the seeds after the compound fruit has fallen to the ground and the hard coat softened by fermentation. Natural stands arise from these seeds. As recently as World War II, a dye was extracted from the wood for khaki uniforms. "Apples" (inset) provided ballast on return trips for boats plying the Red River. Later these "apples" were replaced with goods for shipment, the unloaded fruit providing seeds for living fences far distant from the original narrow range of the species in north-central Texas. The very hard and durable wood, from trees bearing thorns so tough that they puncture truck tires, is harvested throughout the East for specialty products. (USDA Forest Service photo)

Figure 4.3 Ozark Mountain forest of the white oak-black oak-hickory cover type, as climax species, capture many sites. Lands abandoned from agriculture and planted to pines will, before the first rotation is over, begin to appear like these woodlands. (USDA Forest Service photo)

In mountainous regions, hardwood forests cover vast areas to the relative exclusion of both southern and white pines, eastern redcedar, eastern hemlock, red spruce, and Fraser fir. This is true for the Ozark and Ouachita mountains as well as for the Southern Appalachian chain, the Mississippi Bluff Hills of loess soils, and the Post Oak and Cross Timbers of Texas.

Semantics complicates descriptions of upland hardwood forests. Technically, hardwoods are broadleaf trees. Most of them are deciduous, the hollies and magnolias being notable exceptions. Some broadleaf trees have relatively soft wood—yellow-poplar and basswood, for example. Most deciduous trees display broad leaves and produce hard wood.

Much of the southern upland hardwood forests consists of uneven-aged coppice-generated stands of shade-tolerant oaks and hickories arising from roots and stump sprouts. Many of these stems eventually form the climax cover type. That is, climax species cover the land ad infinitum if the forest is left alone, fire is prevented, tree-topping windstorms do not occur, and stands are not harvested.

As a rule, acorns carried by rodents germinate under pines that have taken over abandoned agricultural land after about 10 years. In another few years, hickories seed-in. Where broadleaf trees occur in the harvested forest, reproduction from sprouting begins promptly. Shade-intolerant conifer seedlings eventually give way to deciduous species.

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