Nearctic Cryptic Tundra - Code: Ne10C

Cryptic Tundras, cryptogram barrens, or  High Arctic Vegetation (HAV), are the circumpolar habitat at the extreme north of North America, Europe and Asia, as well as the higher areas, such as ridgelines of the ROCKY TUNDRAS. Most of the surface area of the regions around the poles has no vegetation, so this habitat exists as a mosaic with glaciers and barren rock fields. This is a very uniform habitat where no trees or woody plants are able to grow. Vascular plants such as forbes, grasses, cushion plants, and rosette plants make up less than 10 % of botanical species and only 2% of the biomass, with the remainder dominated by  fungi, algae, lichens, mosses, and liverworts.

 The structure of the tundra can be divided into the three layers, where the “canopy” is a prostrate dwarf shrub layer of less than 5cm (2 in), through this shrub canopy the occasional emergent grass or forbes grow to as high as 10 cm (4in). Much of the ground is completely bare, but where there is a ground covering, it is the cryptogram layer that makes up 60% of what ground over does exist, is generally below 3cm and includes most of the fungi, algae, lichens and mosses.
 
With the exception of polar desert and ice cap, this is the most inhospitable  environment in the world. The very low polar angles mean essentially six months of night and six months of day and less than 4 months with air temperatures above freezing, so little change of snow melt much below surface so permafrost (frozen soil) is a defining feature, and the regions have extremely short growing seasons. The Koppen climate ET is an indication of just how extreme this area is; these tundras experience extremely low temperatures throughout the year; winters are particularly cold, with average temperatures well below freezing, and often as low as  -22 °F (-30 °C). Summer temperatures are relatively milder but still remain very cold, with  average temperatures rarely above 40°F (5°C). Summer temperatures of the Alaskan tundras are determined by latitude with the north being colder than the south. This is very different from the warmer European arctic which is moderated by temperate ocean currents, or the much more severe climates of Siberia and Canada where the coldest temperatures are affected by extreme continentality. This is why  cryptic tundra is much farther south in central Canada than in Alaska or the eastern seaboard.

The regions are usually very dry, with precipitation usually around 12 in  (300mm) (12in) with most of the precipitation from snow, which paradoxically does not usually fall in winter. This low precipitation level in most  locations on the planet would dictate that the habitats be deserts, but the low evapotranspiration rates mean that some surface waters are usually present in summer and the habitat can give of the impression of being humid.  In contrast with the Rocky Tundra, even the better protected snowbanks cannot support shrubs.

Extremely little chemical weathering occurs here and almost all weathering is mechanical such as freeze-thaw weathering and abrasion, resulting in lithosols where changes in underlaying rock chemistry from acid to alkaline are the main determinant of the individual plants which grow there. Calcarious rocks such as limestones are dominated  by Wooly Feather Moss (Tomentypnum nitens) and Dicaranium Fork Moss (Dicranum angustum). On more acidic soils formed on igneous rock such as granites or metamorphic rocks such as schist, the fructose (free standing) lichens Cetrariella delisei,  Cladonia mitis, and Cetraria nivalis are dominant.