JPMayers 1977 MAJOR PRUDHOE VEGETATION CLASSES Barren tundra - B1 B2 dominant in higher microsites. U3 U4 M2 in lower 26 June Pingo Complex - B1 in exposed sites. a. 10 (pools) U5, U6, U7 in snow accumulation areas Frost boil complex - B3 Upland tundra - U2 U3 U4 Upland tundra complex - U3 U4 in higher microsites such as FCP tops. M2 in between, hummocks and in troughs Snowbank complex - U5 or U6 upper reaches of snowbanks usually on steeply sloping terrain. U7 at base Lowland tundra - moist M2 in low; U3 or U4 in higher microsites Lowland tundra - wet M4 in low, U4 or U3 in higher Emergent - shallow E1 Emergent - deep E2 Open water Tundra Stream M5 along moist stream banks; B4 on ground bars, B6 U9 on barren terrace. E1, E2, E4 in stream waters.