temperature proxy, tundra, dendrochronology, soil moisture, early twentieth‐century warming, North Atlantic Oscillation, shrub expansion, dendroecology, dwarf shrubs, climate change, Climatology, Climate, Snow, Growth, Climatic data, Water supply, Oscillations, Summer, Permafrost, Thawing, Polar environments, Shrubs, Global warming, Snow cover, Chronology, R...