Alaska Arctic Tundra Vegetation Map

Introduction - AVHRR false-color composite image - Vegetation Units - Bioclimate Subzones - Floristic Provinces
Substrate Chemistry - Elevation - Lake Cover - Maximum NDVI and Phytomass

NDVI and Phytomass

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This map is nearly identical to the Alaska portion of the maximum NDVI map of the Circumpolar Arctic Vegetation Map. Only the boundaries of the map and scale are changed. Phytomass is included in the NDVI legend instead of being shown as a separate map.

The normalized difference vegetation index (NDVI) shows relative maximum greenness. This image was created from the same data as the AVHRR base image. Vegetation greenness is calculated as: NDVI = (NIR - R)/(NIR + R), where NIR is the spectral reflectance in the AVHRR near-infrared channel (0.725-1.1 µm) where light-reflectance from the plant canopy is dominant, and R is the reflectance in the red channel (0.5- 0.68 µm), the portion of the spectrum where chlorophyll absorbs maximally. The NDVI values were grouped into eight classes related to biomass. Red and orange areas in the NDVI image are areas of shrubby vegetation with high biomass, and blue and purple areas are mostly barren areas with low biomass. The relationship between NDVI and aboveground plant biomass as shown in the legend was calculated from clip harvest data (Walker et al. 2003). For more information refer to the CAVM and supporting papers (Walker et al. 2005, Raynolds et al. in press).