5th Symposium on Fire and Forest Meteorology and the 2nd International Wildland Fire Ecology and Fire Management Congress

Monday, 17 November 2003
Characterizing Post-fire Vegetation Conditions and Trends Using Imaging Spectroscopy
Susan Goodman, Bureau of Land Management, Denver, CO; and R. Kokaly, A. G. McAdams, L. Morath, R. Root, B. Rockwell, and M. McGann
Historically fire has been among the dominant disturbances in the western United States. Following large wildland fires, land managers require information on the post fire state of the land surface to plan hazard mitigation strategies and to guide re vegetation efforts. This paper reports on the use of remotely sensed data collected post wildfire as one such source of information for land managers. Two study areas were investigated one at the location of the Cerro Grande fire that burned in May of 2000 near Los Alamos, New Mexico, and the other is a portion of Bureau of Land Management (BLM) rangeland in central Wyoming, referred to as the Left Hand Creek study site, which has been subject to prescribed fires and wildfires in 2000 and 2001.

Spectral signatures from Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) data collected on September 4, 2000 over the Cerro Grande fire area were examined in relation to known spectral responses of vegetation, mineral and post fire ash materials. Variations in vegetation absorption features arising from chlorophyll and lignin and/or cellulose in conjunction with light detection and ranging (lidar) data collected immediately post-fire indicate that vegetation within fire perimeters potentially can be discriminated into unburned vegetation, fire killed non photosynthetic needles or leaves, and regenerated vegetation. The presence of ash-covered surfaces and bare soil or bedrock surfaces also can be identified and mapped. Hyperspectral Mapping (HyMap) imaging spectrometer data over the Left Hand Creek study area were collected on July 2, 2002. In addition to the remote sensing data collection, field measurements of vegetation reflectance and surveys of plant species composition were made for 33 sites within the study area. Measurements of vegetation cover and species composition were made in order to assess the post-fire temporal dynamics of vegetation community composition in this grassland-sagebrush ecosystem. The HyMap data will be analyzed to estimate the species composition and moisture content of the vegetation canopy, which may in turn be used to develop input information for fire behavior and fire danger rating models. Ongoing efforts in the Cerro Grande and Left Hand Creek study areas seek to utilize post fire characterization of the land surface with in situ studies of erosion and vegetation re-growth to develop predictive models of landscape response following wildland fires.

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