Snowpack Loss Promotes Soil Freezing and Concrete Frost Formation in a Northeastern Temperate Softwoods Stand

Snowpack produces a thermal layer that protects soil from freezing and provides a pulse of nutrient-rich water in spring. Climate forecasts for Maine indicate 20-60% reduction in snowfall by 2050. In January 2015, we initiated a snow-removal experiment in Old Town, ME to investigate the impact of snow loss on forest soil conditions. Snow removal significantly lowered winter organic horizon temperatures by 2 °C on average. Soils in snow-removal plots were 25% wetter during the vernal transition because precipitation was not intercepted by snow. These rain-on-soil events caused the formation of concrete frost, delaying soil thaw in snow-removal plots. Our results provide evidence that snowpack loss increases soil frost and can also increase soil moisture, potentially altering biotic function within a coniferous forest type.