ABSTRACT
Major alluvial floodplains are inextricably connected to major rivers. Major floodplains owe their existence to upstream soil erosion and subsequent deposition of soil particles downstream as the waters lose turbidity. The land building associated with soil deposition causes the river to meander, always seeking an outlet with least expenditure of energy by spreading the gradient over a longer distance. The timber in major alluvial floodplains has been in demand for fruit boxes, shoe heels, paneling for automobiles and houses, flooring, furniture, and decorative items. The most expansive forested floodplains in the southern United States occur along the Mississippi River, where floodplain deposits measure up to 121 km in width over an 800-km range. Flooding alters the chemical properties of alluvial floodplain soils by (1) depositing and replenishing mineral nutrients, (2) producing anaerobic conditions, and (3) importing and removing organic matter. Plant adaptations to water-saturated soils or flooding are divided into morphological type, physiological type, and reproductive type.
