## 3 Results  
### Environmental Conditions  
According to the observations made at meteorological station \"Toropets\", five of six years of the 2015-2020 period were warmer in relation to the long-term means (Table 1); moreover, no years with a negative annual temperature anomaly were observed in the period [51]. The coolest year was 2017, when the mean annual air temperature was equal to the long-term annual mean, and the warmest year was 2020, when the mean annual temperature anomaly reached 1.9 \({}^{\circ}\)C. According to the observations made at the meteorological station \"Lesnoy Zapovednik\", the annual precipitation in 2015 and 2018 was lower than the mean long-term annual sum. Other years of this period were relatively wet, with annual precipitation exceeding the long-term means. The wettest year was 2020, when the annual precipitation exceeded the long-term mean value of 22%. Unlike the mean annual air temperature, the mean air temperature calculated for the long-term growing season (LTGS) period (12 April-11 October) was lower than its mean 30-year value in 2015, 2017, and 2019 and higher than it in other years. The coldest growing season was 2017, and the warmest one was 2018. Precipitation sums were lower than the LTGS mean value in 2015 and 2018 and higher in other years of the period. The driest growing season was 2015, and the wettest one was 2020. The mean winter (1 November-31 March) air temperature was lower than the long-term mean values only in the winter of 2017/2018 (Table 2). Other winters were relatively warm, and a particularly high mean winter temperature was observed in the winter of 2019/2020. The winter air temperature anomalies in the 2015-2020 period were primarily positive, while negative temperature anomalies were generally detected in spring and summer (Figure 2). Precipitation anomalies were differently distributed across the years of measurements. The most significant precipitation anomalies (both positive and negative) were observed in summers. According to the observations made at meteorological station \"Lesnoy Zapovednik\" in the selected years, the surface was covered by snow from November to April with a maximum snow depth of about 40 cm. Under the exceptionally warm conditions that occurred in winter 2019/2020, snow cover was detected only in January and February 2020, with a maximum snow depth of 10 cm [51]. The minimal values of annual global radiation (Table 1) were observed in the wettest and coolest year of the period, 2017. The maximal sum of Rg was detected in the year with relatively dry and warm weather conditions in the growing season, 2018. The daily soil temperature variations followed the air temperature variations, reaching 0 \({}^{\circ}\)C in winter and 17 \({}^{\circ}\)C in summer. Unlike the air temperature, the soil temperature was positive in the winters, and its mean annual value was less variable across the years. The soil water content (SWC) at the site varied between 0.35 and 55 m\({}^{3}\cdot\)m\({}^{-3}\). The maximal values were observed in the springs, shortly after the snowmelts and after the periods of heavy rain occurring in the summer and autumn. The seasonal course of the SWC had a pronounced pattern: after the snow melted, it tended to decrease, and the minimal values were generally observed in August and September before slightly increasing until spring. The minimal value of the SWC obtained for the study period was observed in the summer of 2018, which was the driest year of the period. In the relatively wet growing seasons (2017 and 2020), the summer SWC was usually higher than 45 m\({}^{3}\cdot\)m\({}^{-3}\). The mean annual SWC was correlated with the annual precipitation measured at the meteorological station \"Lesnoy Zapovednik\" (Table 1).