15N natural abundance 1 Abies sibirica 1 Central Austrian Alps 1 Changbai Mountain 1 Erman's birch 1 European Alps 1 Holocene 1 Larix decidua 1 Mediterranean climate 1 NDVI 1 Picea abies 1 Pinus cembra 1 Pinus sibirica 1 Rocky Mountains 1 Southern Ocean 1 Switzerland 1 alpine timberline 1 alpine treeline 1 altitude 1 apical control 1 basal area increment 1 carotenoids 1 chlorophyll 1 climate change 1 climate warming 1 climate zone 1 cloud 1 conifer shrub conifers 1 dendroclimatology 1