Normalized Difference Vegetation Index and Total Vegetation Fractional

Combining satellite indices that measure plant greenness and vegetation cover can be used to identify vegetation changes that are not apparent using a single index alone. The Normalized Difference Vegetation Index (NDVI, top) is a measure of greenness based on the near-infrared wavelengths, while the Total Vegetation Fractional Cover (TVFC, bottom) is based on the shortwave-infrared bands and provides a good estimate of both green and senescent vegetation cover. These two graphs show index values at sites with no fire (pink), four fires (blue) and five fires (green and red) between 1985 and 2011. The TVFC shows a clear response to fire (i.e. drop in cover in 1986 followed by recovery). TVFC values begin to diverge considerably after fires occur during drought periods (post-2000).