Interaction of Vegetation and Soil Frost Phenomena

Abstract

"The influence of soil frost on plants and of plants on soil frost is discussed. Permafrost can not be penetrated by living roots, and if at a shallow depth, it imposes limitations on the anchoring functions of tree roots in shallow soils. Frozen ground inhibits lateral movement of soil water and prevents downward percolation. Sites for vegetation are destroyed by progressive thawing of permafrost. Soil surfaces are in places rendered unavailable to plants because of soil stirring, sorting, and transport by frost action as manifested by polygons, pitted tundra, and soil stripes. Plants affect soil frost phenomena by exercising controls on the thermal regime of the soils. Vegetation shields the soil from maximum penetration of heat by shading, decreasing air circulation, retaining moisture in and just above the soil, and by intercepting rain. It is shown that mosses provide a cooling effect, because of low thermal conductivity, large waterholding capacity, and high hygroscopicity. Extensive root systems tend to impede downward percolation of water, thus restricting thaw. Applications of soil frost predictions, on agriculture, forestry, and construction are considered, and future investigations are proposed."--SIPRE. Bibliography (31 items).