The Circumpolar Arctic Vegetation Map (CAVM) project is aninternational effort to map the vegetation and associatedcharacteristics of the circumpolar region, using a common base map. Thebase map is a false color infrared image created from Advanced Very High Resolution Radiometer (AVHRR) satellite data. Get a more detailedoverview at About the CAVM.
Description of Arctic bioclimate subzone categories A-E As one moves from north to south across the Arctic, the amount of warmth available for plant growth increases. The mean July temperatures are near 0C on the northernmost islands. At these temperatures, plants are at their metabolic limits, and small differences in the total amount of summer warmth make large differences in the amount of energy available for maintenance, growth, and reproduction. Warmer summer temperatures cause the size, horizontal cover, abundance, productivity and variety of plants to increase (see Table 2 CAVM). Woody plants and sedges are absent in Subzone A, where mean July temperatures are less than 3C. Woody plants first occur in Subzone B (mean July temperatures about 3-5 C) as prostrate (creeping) dwarf shrubs, and increase in stature to hemiprostrate dwarf shrubs (<15 cm tall) in Subzone C (mean July temperatures about 5-7C, erect dwarf shrubs (<40 cm tall) in Subzone D (mean July temperature about 7-9C), and low shrubs (40-200 cm tall) in Subzone E (mean July temperature about 9-12C. At treeline, where the mean July temperatures are between 10 and 12C, woody shrubs up to 2 meters tall are abundant. The number of plants in local floras available to form plant communities increases from fewer than 50 species in the coldest parts of the Arctic to as many as 500 species near treeline.