Data on the distribution of plant communities, their productivity, and major carbon stores held in mountain tundra vegetation and soils are presented. Extreme snow-bed communities had the lowest total biomass (662 g/m2), primarily in the main root portion in mineral soil horizons. Dwarf shrub–dominated heath on a gentle mountain slope had the highest total biomass (2406 g/m2), with woody perennial stems prevailing in the above-ground portion, and the main root portion concentrated in the organic horizon. Grass and sedge meadows situated in a hollow had the greatest total net primary production (215 g/m2), and roots were evenly distributed throughout the soil profile. The total amount of carbon stored in the ecosystem included carbon stored in above- and below-ground biomass, in the organic horizon, and in mineral soil horizons to a depth of 30 cm. Total carbon was lowest in snow-bed and lichen-dominated tundra (6183 g/m2 and 6337 g/m2, respectively), and highest in dwarf shrubs and grass-dominated tundra (25,261 g/m2 and 20,407 g/m2, respectively), the latter being comparable to total carbon stored in boreal forest ecosystems. Most of the carbon (95–97%) in tundra ecosystems was stored in soils (organic and mineral soil horizons).