Fire Ecology Project - Joseph W. Jones Center
We are investigating the interactions that fire and water availability play on ecosystems carbon dynamics in two longleaf pine ecosystems that occur along a natural moisture gradient. Research will combine field measurements and field manipulations to address the role and consequences of fire on carbon dynamics of frequently burned longleaf pine ecosystems in the Southeastern US and how changes in climate as predicted by climate models will influence fire and productivity and ultimately the carbon sequestration capacity of these ecosystems.
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Alaska Project - Toolik Field Station- North Slope Alaska
The overarching goals of this project are to: 1) fill the large gap in our understanding of physiological processes of arctic tundra vegetation during the cold season, and 2) determine how these physiological processes contribute to the carbon dynamics of the ecosystem under current environmental conditions and scenarios of climate warming.
The urgency for the project arises in light of two facts. First, the presence of approximately 450 Pg of carbon precariously stored in cold wet soils in tundra systems could be oxidized to the atmosphere as the soil conditions change. Secondly, a shift toward increased shrub cover in the Arctic is hypothesized to be a result of cumulative interactions among cold-season processes. A comprehensive understanding of cold-season physiological processes of tundra vegetation is critically needed given the large potential for further climate changes in the Arctic. |
Everglades Project
Our objectives are to: 1) Quantify seasonal patterns of CH4 and CO2 fluxes from the two dominant marsh types in the Florida Everglades, short- (marl soil) and long- (peat soil) hydroperiod Everglades marshes, 2) Determine the relative contributions of CO2 and CH4 fluxes to ecosystem carbon dynamics in short- and long- hydroperiod Everglades marsh over different special and temporal scales, 3) Determine how the interaction of these greenhouse gases affects the Everglades Global Warming Potentials at varying scales. To relate fluxes to background water levels and nutrient loads, two solar-powered flux towers are sited near water level recorders and nutrient autosamplers and productivity sample sites of the Florida Coastal Everglades (FCE) LTER program. Data is linked with ongoing productivity measurements and modeling efforts of the FCE LTER. This project has been in operation since August 2008.
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Building forest management into Earth system modeling: Scaling from stand to continent
This project addresses these questions: 1) how do climate, management, and disturbance interact with forest ecosystem function at regional to continental scales, 2) do these interactions behave in a non-linear fashion when compared to those of the stand, and 3) how can we improve fundamental theories linking forest structure to function at the macrosystem scale? The over-arching objectives of our study are to determine how the variations in forest management, climate, and disturbance impact the structure and function of forest ecosystems, and quantify the relative importance of forest management, climate, and disturbance as drivers of ecosystem structure and function at stand to continental scales across North American forests.
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Understanding the environmental drivers of water use efficiency from a Woody Bioenergy Crop using Eddy Covariance Techniques
The US Energy Independence and Security Act of 2007 mandates substantial increases in biofuel production to occur over the next decade to achieve the national “renewable fuel standard”. In developing bioenergy feedstocks, the United States Departments of Agriculture and Energy have focused on cellulosic plant materials that can be converted to advanced biofuel and grown on soils and watersheds considered marginal for production of food (DOE 2011). However, when considering the use of these cellulose based crops, there is an uncertainty regarding the quantities of water these rapidly growing products will use and if this will have negative outcomes on water resources at local to region scales. Our project will provide estimates of stand level evapotranspiration (ET) rates for the loblolly biofuel crop over the first 3 years of stand development using eddy covariance (EC) techniques. This project supports the USDA mission by providing essential data that will help identify how the bioenergy feedstock of loblolly pine affects water quantity in proposed regions of cultivation. Determining water use of intensively managed pine is timely, given the recent construction of an advanced biofuel facility by KiOR, Inc. in Mississippi to convert pine and hardwood residues as well as pulpwood-size materials to fuel under the RFS2, and the interest and expansion of plantations by landowners to replace southern hardwood pulp supplies. Our dataset will also be available to enhance mechanistic models about regional water dynamics for these ecosystems by adding a level of detail on the interaction of stand development and climate variation which has been limited in previous studies.