Impact of climate change on soil frost under snow cover in a forested landscape

This study was aimed at assessing the potential impacts of climate change on the depth and duration of soil frost under snow cover in forests growing at different geographical locations in Finland. Frost simulations using a process-based forest ecosystem model (FinnFor) were made for Scots pine Pinus sylvestris L. stands (height 17 m, stand density 1100 stems ha(-1)) growing on a moraine sandy soil. The climate change forecast used in the computations was based on the global ocean-atmosphere general circulation model HadCM2 that was dynamically downscaled to the regional level. The simulated climate warming during the winter months was about 4 to 5 degreesC by the end of the 21st century. Frost simulations showed that the length of the soil frost period would lessen all over the country. Though winters will be warmer, the associated decrease in snow cover in southern Finland will increase the probability of frozen ground there in the middle of winter compared with the current climate. In central and northern Finland there will be so much snow, even in the future, that the maximum annual soil frost depth will decrease there.