Date of Award

1997

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Renewable Natural Resources

First Advisor

Jim L. Chambers

Second Advisor

Wayne H. Hudnall

Abstract

Wetland delineation in bottomland hardwood forests is controversial due to uncertainty of the duration of inundation and soil saturation on seasonally dry sites. Wetland delineation requires an assessment of hydrophytic vegetation, hydric soils, and wetland hydrology. The objectives were to: (i) classify forest types in five Wildlife Management Areas in central Louisiana within Sharkey clay and Fausse clay soil mapping units, (ii) compare site and soil variables between the forest types, (iii) evaluate relationships between tree species distributions and soil/site factors, (iv) characterize soils in the study area, (v) evaluate differences in forest types for durations of inundation, soil saturation, and soil chemical reduction. Five forest types were classified in the study area and named for their dominant species: Sugarberry (Celtis laevigata Willd.), Overcup Oak (Quercus lyrata Walt.), Water Hickory (Carya aquatica (Mich.f.) Nutt.), Black Willow (Salix nigra Marsh.), and Baldcypress (Taxodium distichum (L) L. C. Rich.). The Sugarberry forest type predominantly occurred on Sharkey clay soil mapping units with occasional flooding frequency, and the Black Willow and Baldcypress forest types occurred solely within the depressional Fausse clay soil mapping units having the longest inundation. Baldcypress forest type soils had the highest organic matter content and lowest pH among all the forest types. All soils characterized were very fine or fine textured, and had high cation exchange capacities (30-50 cmol(+)/kg). The Sharkey soils were classified as very-fine, smectitic, thermic Chromic Epiaquerts, and met field indicators of hydric soils. Soils in identical landscape positions on Red River alluvium were classified as very-fine or fine, smectitic, thermic Aeric Epiaquerts, and mostly did not meet field hydric soil indicators. Soils in the study area were episaturated during winter and spring. The Sugarberry forest type had the shortest durations of inundation, soil nitrate reduction, and soil iron reduction among the forest types. The Black Willow and Baldcypress forest types were inundated and chemically reduced longer than the other forest types. All forest types were predominantly wetland, but the Sugarberry forest type had the least hydrophytic vegetation, met the fewest hydric soil indicators, and had the shortest duration of wetland hydrology among all five types.

ISBN

9780591724103

Pages

248

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