ABSTRACTStudies of the ground temperatures and hydrological conditions at four sites on a subalpine heath and in the birch forest in the subarctic valley in Abisko from 1984–87 show that a clear relationship exists between ground temperature and climatic parameters, especially precipitation through the effects of snow cover. The effects of precipitation poor summers in 1985–87 and the colder than normal and snow poor winters of 1985 and 1987 were instrumental in intensifying the effects of seasonal frost at all of the sites.