The Montane Forest Dynamics Lab’s research interests include biogeography, forest dynamics, and human and climatic causes of ecological change. We like to apply a variety of methods, such as vegetation sampling, dendrochronology, and spatial analysis to answer questions about human interactions with ecological systems. Current projects, including those of my graduate students, are described below.
The success of the Mongol Empire, the largest contiguous land empire the world has ever known, is a historical enigma. At its peak in the late 13th century, the empire controlled or influenced areas from the Hungarian grasslands to Syria, Bagdad, Vietnam, and Japan. Powered by domesticated grazing animals, the Mongol Empire grew at the expense of sedentary agriculturalists living in Eastern Europe, Persia, and China. What environmental factors contributed to the rise and decline of the Mongols? Until now, little high resolution environmental data have been available to address this question. Our recent discovery of ancient sub-fossil wood on a lava flow in central Mongolia allows, for the first time, high resolution reconstructions of the past environmental conditions during the rise of the Mongol Empire. Longstanding speculation is that drought during the early 13th century was a major driver in leading the Mongols to conquer Asia and Eastern Europe. Our preliminary record indicates the opposite: the rise of the Mongols occurred during an extended, warm and wet pluvial. We hypothesize that this climatic optimum led to high grassland productivity and Mongol expansion. To test this hypothesis, we will reconstruct drought and grassland productivity, the basis of energy and carrying capacity for the Mongolian herding culture, over the last 2000 years using a more complete sample of tree-ring records available at Khorgo Lava.Collaborators on this project include:
- Neil Pederson, Lamont-Doherty Earth Observatory, Columbia University
- Baatarbileg Nachin, National University of Mongolia
- Kevin Anchukaitis, The University of Arizona
- Nicola Di Cosmo, Institute for Advanced Study
- Avery Cook Shinneman, University of Washington
- Hanqin Tian, Auburn University
- Laia Andreu-Hayles, Columbia University
Fire History and Climate in Mongolia
Amy Hessl has worked for more than ten years on relationships between fire and climate in western North America and more recently in central Asia (Mongolia). In 2008, Neil Pederson (Eastern Kentucky University), Peter Brown (Rocky Mountain Tree-Ring Research), Nachin Baatarbileg, (National University of Mongolia) and Amy Hessl were awarded an National Science Foundation grant (Ecosystem Sciences) to explore the fire history of Mongolia’s arid forests. This project developed following the 2006 International Dendrochronological Fieldweek in Mongolia and is focused on exploring the relationship between fire, climate and forest history in the context of climate change. Learn more here.
Reconstructing Climate from Eastern Redcedar
Two of Amy Hessl’s graduate students (Dr. Richard Stockton Maxwell and Josh Wixom) have been pursuing a variety of studies of Eastern Redcedar (Juniperus virginiana). Eastern Redcedar is long lived (700+ yrs.) on limestone outcrops of the Ridge and Valley province. In addition, sub-fossil wood is preserved for several centuries on dry sites. For his dissertation, Stockton developed a millennial-length hydroclimatic reconstruction of Potomac River flow using his eastern redcedar samples in combination with other tree ring records. We are also taking a multi-proxy approach to reconstruct hydroclimate variables, including C and O isotopic signatures recorded in the tree rings (Richard Thomas, WVU Biology). This long reconstruction would allow water managers to gain a long term perspective on 20th and 21st century droughts and pluvial events.
This research is supported by the National Science Foundation (Dissertation Improvement Grant, Geography and Spatial Sciences, to Stockton Maxwell) and the WVU Eberly College of Arts and Sciences.
Cliff Ecology in the New River Gorge, WV
Amy is currently collaborating with Dave Smaldone (WVU Recreation, Parks and Tourism), Steve Kite (WVU Geology) and the National Park Service to survey the cliff vegetation in the Gorge and evaluate the impacts of climbing on both vascular and non-vascular plants. Pete Clark, an MA student working with her, is an accomplished climber and botanist. His masters research will for the first time, define the relationship between climbing intensity and impact on vegetation. This work is supported by the National Park Service, The Access Fund, and The Explorers Club, DC.