Piecing together the past floodplain forests of the Yazoo Basin in the Mississippi Delta, Lower Mississippi Alluvial Valley, USA

Abstract

Productive, large alluvial basins have been converted to agriculture, with limited retained vegetation and concomitant incomplete information about the historical vegetation before land use changes. The Yazoo Basin, a 1.7 million ha study extent as defined by 11 counties in the Mississippi Delta of the Lower Mississippi Alluvial Valley (LMAV) in the southeastern United States, currently is 70% croplands, but the historical forests of the region have not been quantified. Therefore, we recovered historical tree species composition and forest structure from land surveys conducted during years 1823 to 1845, and contrasted historical forest composition to limited samples from current tree surveys, given that current forest extent has been minimized by land use. Overall, 75% of 42,105 historical trees (≥12.7 cm in diameter at breast height; DBH) showed unique dominance by sugarberry (Celtis laevigata) along with oaks (Quercus), sweetgum (Liquidambar styraciflua), elms (Ulmus) and ashes (Fraxinus), and moderate components of hickories (Carya) and maples (Acer). While current tree composition was similar, current inventories indicated decreased proportion of sweetgum (-4.1 percentage points) and oaks (-2.9; likely white oak, Quercus alba, in uplands) with increased proportion of loblolly pine (Pinus taeda,+3.1), although probably most historical tree species have decreased, due to agricultural conversion. Because upland oaks have decreased to less than 2% of all trees, with only a small change in overall oak percentages, lowland oaks, including Nuttall’s oak (Quercus texana) and willow oak (Quercus phellos), may have increased. Historical density estimates suggested that forests were dense. However, based on surveyor descriptions, overall forests were embedded in an inundated, rivercane (Arundinaria gigantea)-filled landscape in the Yazoo Basin, indicating disturbance by flooding and fire. Ecosystem services can be supplied by the remaining floodplain forests, which are located in marginal lands for agriculture.

Citation

Hanberry, Brice B.; Tatina, Robert. 2026. Piecing together the past floodplain forests of the Yazoo Basin in the Mississippi Delta, Lower Mississippi Alluvial Valley, USA. Trees, Forests and People. 26: 101345.