Frost heaving in a boreal soil in relation to soil scarification and snow cover

Vertical uplift of seedlings and rods on the soil surface and at a depth of 5 cm, and of reference trees, was monitored using a theodolite from autumn to spring in two adjacent field experiments on a silt soil in northern Sweden. Treatments involving scarification (control and square patches of 0.1, 0.2, 0.4, and 0.8 m at natural snow cover) and snow cover (simulated maximum cover, snow free, and natural cover for control and 0.4-m patches) were compared. For snow free and natural snow cover, diurnal variation of soil surface temperature, duration and magnitude of freezing temperatures, and uplift increased with patch size. At the end of the winter under natural snow cover, uplift of the soil surface and shallow soil was between 4.4 and 5.3 cm for the control treatment without scarification and the 0.1-m patch while the uplift for the 0.4- and 0.8-m patches reached 7.6–11.5 cm. The highest uplift value, 14.6 cm, was observed for the snow-free treatment with 0.4-m patches. Maximum uplift of trees averaged ...