Active Layer
25 " H x 25" W

Embroidery on silk and velvet

The portion of the soil above permafrost that thaws and freezes seasonally is the active layer.

It plays an important role in cold regions because most ecological, hydrological, biogeochemical and soil forming activity takes place within it. Changes in active layer thickness are invluenced by many factors including surface temperature, physical and thermal properties of the surface cover and substrate, vegetation, soil moisture and duration and thickness of snow cover.