Assessment of hurricane-related disturbances in US forest ecosystems

Robinson Negron-Juarez, Tulane Unviersity, rjuarez@tulane.edu (Presenter)
Jeffrey Q. Chambers, Lawrence Berkeley National Laboratory, jchambers@lbl.gov
George Hurtt, University of Maryland, gchurtt@umd.edu
Justin Fisk, University of Maryland, fisk@umd.edu

Tropical cyclones produce drastic disturbance to the U.S. forest ecosystem by altering forest structure, species composition, nutrient cycling,biomass accumulation, etc. The recurrent characteristics of these events demand a rapid yet reliable

assessment of forest disturbance in order to provide better management decisions, as well as to evaluate damage to the landscape, biomass loss and the associated impacts to the regional carbon budget. In this study we present a methodology for rapid assessment of hurricane-related forest disturbance based on maximum sustained hurricane wind swaths (H*wind), MODIS (Moderate Resolution Imaging Spectroradiometer)-derived disturbances and field-measured tree mortality collected in Gulf Coast forests. MODIS images in May (the month of maximum greenness) before the disturbance and in May of the year following the disturbance were processed using spectral mixture analysis (SMA) using endmembers as green vegetation, non-photosynthetic vegetation and shade. The changes in non-photosynthetic vegetation (ΔNPV, related to wood, dead vegetation and surface litter) from one year to the next was used as the disturbance metric. A strong correlation was found between H*wind and MODIS ΔNPV for hurricanes Charley (2004), Katrina (2005), Rita (2005), and Gustav (2008). In turn, MODIS ΔNPV was shown to have a strong correlation with field-measured mortality. The forest disturbance estimates based on hurricane wind-field and MODIS ΔNPV agree with those published in our previous studies. This study establishes an important relationship that could be incorporated into earth system models to improve our understanding of the effect of tropical cyclones on terrestrial ecosystems and their associated feedbacks within the climate system.

Presentation Type:  Poster

Session:  Coupled Processes at Land-Atmosphere-Ocean Interfaces   (Mon 4:00 PM)

Associated Project(s): 

• Hurtt, George: Modeling the Impacts of Major Forest Disturbances on the Earth's Coupled Carbon-Climate System, and the Capacity of Forests to Meet Future Demands for Wood, Fuel, and Fiber ...details

Poster Location ID: 58