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Physical Geography


Biogeography is the study of the changing distributions of species and groups of species in space and time, and the physical, biological, and cultural factors that influence distribution patterns. Two faculty members, Sally Horn, and Liem Tran conduct research related to vegetation patterns and their controls over recent and long time scales. Biogeographical topics that have engaged department faculty and their students include: fire as an influence on vegetation patterns in the southern Appalachians, western United States, circum-Caribbean, and Mozambique; landscape-scale assessment and modeling of vegetation, climate, and human impacts; modern lake environments and biota; the origins and spread of domesticated plants; the biogeographical consequences of the European Conquest of the New World; and the impacts of Quaternary climate change, drought, and human activity on plants and vegetation across North and South America. These projects make use of the Laboratory of Paleoenvironmental Research, and other department laboratories.

Climate and Environmental History

Research on paleoclimate and paleoenvironments contributes to answering fundamental questions about the functioning of Earth’s climate system, “natural” disturbance regimes in ecosystems, and the role of humans in changing the environment, and has important applications in designing conservation and land-management plans. Unraveling the past history of world environments also improves our knowledge of future global change. The University of Tennessee Department of Geography has a strong program of research involving the reconstruction of past environmental conditions—climate, vegetation, fire, ecosystem disturbances, and human activity—from natural archives that include tree rings, soils, and lake sediments. Two faculty members (Sally Horn and Yingkui Li) and their students are active in paleoclimate and paleoenvironmental research funded by the National Science Foundation and a variety of other agencies. The department has world-class laboratories for the study of tree rings (under the direction of Sally Horn) and for cosmogenic nuclide dating and analyses of pollen, charcoal, and other proxy indicators in sediments and soils (Laboratory of Paleoenvironmental Research, directed by Horn and Li). Adjunct faculty member Chad Lane (University of North Carolina Wilmington) brings expertise in isotope geochemistry, and serves on several student committees. The University of Tennessee’s Initiative for Quaternary Paleoclimate Research, currently directed by Horn, is housed in Geography (, and faculty collaborate with colleagues in Earth and Planetary Sciences, Anthropology, and Ecology and Evolutionary Biology in studies of past climate and environment from natural archives.

Geomorphology and Soils

Geomorphology is the study of landforms and the processes that shape them.  Soils are byproducts and archives of landform evolution as well as regulators and recorders of surface and near-surface environmental conditions. Four faculty members, Carol Harden, Liem Tran, Yingkui Li, and Sally Horn, conduct research in process geomorphology (fluvial, hillslope, glacial) and/or study soil processes or soils as archives of previous environmental conditions. Research themes have included soil erosion, soil-water relations, sediment linkages between land and stream, glacial history, cosmogenic isotope nuclide dating of landforms and sediments, paleoclimate inferences from paleosols, and fire histories based on soil charcoal.  The department has labs equipped to analyze physical characteristics of soils and sediments, and to prepare samples for cosmogenic nuclide dating. Members of the Geography faculty collaborate with colleagues in Biosystems Engineering and Soil Science, Earth and Planetary Sciences, and Civil and Environmental Engineering in research involving geomorphology and sediments.

Human-Environment Interaction and Water Resources

Landscapes change as human activities change or persist over time. These dynamics, in turn, affect decisions about land use and environmental management. Liem Tran, Yingkui Li, and their students conduct research to identify, characterize, and model environmental effects of human activity and land-use change. Much of their research focuses on water resources, and on surface hydrology, drought, water quality, and watershed dynamics at scales from headwater catchments to integrated regional assessment. They work with local agencies, including TVA (Tennessee Valley Authority) and TDEC (Tennessee Department of Environment and Conservation), in field-based and model-based studies of local water-related issues. Dr. Liem Tran developed a framework called Regional Hydrologic Modeling for Environmental Evaluation (RHyME2) for hydrologic modeling across scales. Tran works with the EPA’s Regional Vulnerability Assessment program to model regional-scale environmental conditions, anticipate future issues, set management and ecosystem protection priorities, and proactively assess decisions that may involve tradeoffs.  Dr. Yingkui Li has focused his water-related research on the Tibetan Plateau and Central Asian highlands.  Geographers collaborate in interdisciplinary research on water resources through the Water Resources Research Center and the Watershed Faculty group at The University of Tennessee.