The Apalachicola River is part of a 50,800-square-kilometer drainage basin in northwest Florida, Alabama, and Georgia. The river is formed by the confluence of the Chattahoochee and Flint Rivers at Jim Woodruff Dam and flows 171 kilometers to Apalachicola Bay in the Gulf of Mexico. Its flood plain supports 450 square kilometers of bottom-land hardwood and tupelco-cypress forests. The most common trees, constituting 62 percent of the total basal area, were five wet-site species; water tupelo, Ogeeche tupelo, baldcypress, Carolina ash, and swamp tupelo. Other common species were sweetgum, overcup oak, planertree, green ash, water hickory, sugarberry, and diamond-leaf oak. Five forest types were defined based on species predominance by basal area. Biomass increased downstream and was greatest in forests growing on permanently saturated soils. Water and tree relations varied with river location because range in water-level fluctuation and topographic relief in the flood plain diminished downstream. Heights of natural...