Migration of the northern evergreen needleleaf timberline in Siberia in the 21st century

Abstract

An analysis of the shift of the northern boundaries of closed evergreen coniferous (EGC) stands in Siberia was carried out based on the time series of vegetation cover maps (2001-2016) obtained from MODIS satellite imagery data. The northern boundaries of the EGC for two studied periods (2001-2003 and 2014-2016) were identified. Mostly, a shift of the EGC boundary in the north direction (by ~26±2 km) was revealed. An increase in the area of the closed EGC stands (by 15-50 %) contributed to the expansion of their boundaries was not uniform depending on the relief. In Western Siberia, the increase mainly was observed at altitudes of 100-130 m above sea level, and on the Central Siberian plateau - at 350-500 m. The EGC boundary locates in the zone of mean summer temperatures 12-15 °C. In the study area in 1970-2000s, a warming period was observed (temperatures increased by ~0.5-1.5 °C, p < 0.05). The given temperature regimes facilitated an increase of closure of the EGC stands (by ~1-3 %/year), their expansion to the north, and upward along the elevation gradient. In the zone of intensive anthropogenic impact (oil and gas fields of the Vankor cluster and the Yamalo-Nenets Autonomous Area), a shift of the EGC boundary to the south was observed. © 2020 Space Research Institute of the Russian Academy of Sciences. All rights reserved.