Song, Conghe: University of North Carolina Chapel Hill (Project Lead)
Hwang, Taehee: Indiana University Bloomington (Co-Investigator)
Novick, Kim: Indiana University (Co-Investigator)
Coulston, John: USDA Forest Service (Collaborator)
Vose, James: USDA Forest Service (Collaborator)
Project Funding:
2017 - 2020
NRA: 2016 NASA: Carbon Cycle Science
Funded by NASA
Abstract:
The southeastern US is characterized by generally abundant in precipitation and high radiation inputs; therefore the gross and net primary productivity (GPP and NPP, respectively) of the region are high, making it a major carbon sink in the conterminous US. NPP is also the basis for food and fiber provision and sustaining vital ecosystem services. Over the last two centuries, this region has experienced a remarkable disturbance history characterized by widespread clearcutting and then reforestation under active land management that includes a focus on intensive forest management. More recently, the combination of human population growth, rapid expansion of urban areas, and forest management practice has resulted significant LULC changes in many areas of the southeast, but especially in the piedmont regions and along some coastal areas. Regional carbon cycling is undoubtedly linked to this management history, yet the mechanisms by which historical and future land management decisions determine the magnitude and variability of the regional carbon sink have not been elucidated. Moving forward, the ability of the southeastern landscape to requester carbon could be substantially altered by climate changes. For example, the region recently experienced unprecedented droughts in 2001 and 2007, and a severe ice storm in 2002, all of which substantially reduced the primary productivity in the region. According to the most recent IPCC report, we can expect more frequent and severe extreme weather in the future, which could promote large inter-annual variation in ecosystem productivity, and alter disturbance regimes that could have long lasting impacts on the primary productivity and carbon sequestration; however, our current understanding of such impacts on GPP and NPP are poorly. To better quantify and understand these impacts, we will use the rich remote sensing data available for this region, that include historical air photos, long time series of Landsat imagery, recently collected LiDAR, MODIS as well as Sentinel-2 from ESA. The remotely sensed data will be used synergistically to reconstruct the LULC change through time, including changes in LULC categories as well as species composition as a result of forest succession. The LULC history reconstructed from remote sensing will be used as input to an ecosystem productivity model to disaggregate the impacts of climate and LULC changes on primary productivity, respectively. We will use US Forest Service’s Forest Inventory Analysis, AmeriFlux data as well as the high quality stream flow data from USGS for model calibration and evaluation. We intend to address the following questions: (1) what are the historical trends in the patterns of LULC, and species composition in US Southeast since the 1950s? (2) How have the changes in forest extent and composition altered gross and net primary productivity? (3) How, and to what extent, does the combination of the historical trends in climate and LCLU impact the vulnerability of carbon storage in the southeast in the past and in the future? Answers to these questions are critical for sustainable development planning in this region, given the high ecological and economic importance of southeastern U.S. forest ecosystems.
Publications:
Dannenberg, M. P., Song, C., Hakkenberg, C. R. 2018. A Long-Term, Consistent Land Cover History of the Southeastern United States. Photogrammetric Engineering & Remote Sensing. 84(9), 559-568. DOI: 10.14358/PERS.84.9.559
Hwang, T., Gholizadeh, H., Sims, D. A., Novick, K. A., Brzostek, E. R., Phillips, R. P., Roman, D. T., Robeson, S. M., Rahman, A. F. 2017. Capturing species-level drought responses in a temperate deciduous forest using ratios of photochemical reflectance indices between sunlit and shaded canopies. Remote Sensing of Environment. 199, 350-359. DOI: 10.1016/j.rse.2017.07.033
Kim, J. H., Hwang, T., Yang, Y., Schaaf, C. L., Boose, E., Munger, J. W. 2018. Warming-Induced Earlier Greenup Leads to Reduced Stream Discharge in a Temperate Mixed Forest Catchment. Journal of Geophysical Research: Biogeosciences. 123(6), 1960-1975. DOI: 10.1029/2018JG004438
Kim, J., Hwang, T., Schaaf, C. L., Kljun, N., Munger, J. W. 2018. Seasonal variation of source contributions to eddy-covariance CO2 measurements in a mixed hardwood-conifer forest. Agricultural and Forest Meteorology. 253-254, 71-83. DOI: 10.1016/j.agrformet.2018.02.004
More details may be found in the following project profile(s):