DENDROLOGY

Detailed explanation-1: -Tundra winters are long, dark, and cold, with mean temperatures below 0°C for six to 10 months of the year. The temperatures are so cold that there is a layer of permanently frozen ground below the surface, called permafrost. This permafrost is a defining characteristic of the tundra biome.

Detailed explanation-2: -The Arctic’s permafrost, the literal foundation for much of the region’s unique ecosystem, is deteriorating with the warmer global climate. Permafrost is a layer of frozen soil and dead plants that extends some 450 meters (1, 476 feet) below the surface.