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- Info
Deriving dynamic information on fire fuel distributions in southern California chaparral from remotely sensed data
| Author: |
Stow, Douglas; Hope, Allen; McKinsey, David; Pray, Heather |
| Date: |
1993 |
| Periodical: |
Landscape and Urban Planning |
| Abstract: |
The major objective of the research reported in this paper was to perform a pilot study for mapping fire fuel properties of southern Californian chaparral shrubs and associated forest ecotones using multi-date (seasonal) Landsat Thematic Mapper (TM) image data. Information on past, current and future (predicted) distributions of vegetation properties pertaining to fire fuels are necessary for understanding, monitoring, managing and modeling fire in changing Mediterranean landscapes. Seasonal and interannual variability of some vegetation properties can be extracted from multi-date remotely sensed data that may provide useful information pertaining to fire fuel distributions. Brightness (BR), Greenness (GR) and Wetness (WT) transform images were derived from two geometrically and radiometrically registered TM images acquired in San Diego County, California, USA, near the beginning and end of the 1986-1987 growing season. Seasonal difference images of these transforms were also generated. Transform and difference values were stratified by vegetation community type and stand age or slope aspect, using an existing raster geographic information system database. The BR and GR images provided unique spatial information pertaining to vegetation conditions. Seasonal change in BR was highest for burn and meadow areas, while high values in seasonal change in GR corresponded to deciduous oak woodlands, grasslands and vegetated north facing slopes. End-of-season GR for Mixed Chaparral varied with stand age in a manner which was similar to field measurements of total and live standing biomass. Differential illumination effects seem to dominate spatial variations in BR and GR values and their seasonal change as a function of slope aspect. |
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