Winter soil temperature at the snow cover manipulation experiment in boreal forest

The study was conducted in a spruce forest near Syktyvkar, taiga zone of northwestern Russia (N 61.650429, E50.731707). The mean annual air temperature is 0.5 C, with an annual precipitation of about 620 mm. Snow cover duration is averages 6 months (November-May). The stand is dominated by Norway spruce (Picea abies), but other species including Betula pubescens and Populus tremula are interspersed. There are sparse shrubs of rowan (Sorbus aucuparia) and dog rose (Rosa canina). The herbaceous layer is dominated by Oxalis acetosella and Vaccinium uliginosum. Less abundant herb species are Maianthemum bifolium, Pyrola rotundifolia, and mosses Hylocomium splendens, Pleurozium schreberi, Rhytidiadelphus triquetrus. In November 2018, three experimental plots (3 × 6 m) were established. The distance between the plots was at least 100 m. Each plot was divided into two sub-plots (3 × 3 m); each sub-plots corresponded to one option. The first option provided for the absence of snow cover in winter, which was achieved by the construction of sheds (a wooden frame covered with polyethylene film). The height of the sheds was 1 m. The fallen snow was regularly removed from the sheds to prevent their destruction. The second option was the control and did not involve any manipulations. The soil temperature was recorded eight time a day from November 2018 to May 2019 using a HOBO U12-008, ONSET, which was installed 5 cm below the soil surface at each sub-plot.