Dendroclimatic Relationship of Sampling Mountain Birch

Arctic treelines have been used as global indicators of climate change. Study has shown that terrestrial vegetation has migrated up-and-down mountain sides throughout the Holocene. Mountain birch (Betula pubescens subsp.czerepanovii) is the dominant treeline species in northern Sweden. There has been extensive research on how mature mountain birch responds to change in temperature and precipitation. However, there has not been a comprehensive study on how mountain birch trees respond. This study evaluates the potential changes in the sapling mountain birch trees across the treeline in northern Sweden. Data from mountain birch tree-ring chronologies from sixty-nine field sites in northern Sweden are used to create a tree ring width index, and explores its relationship to climate. Three global climate models are then used to predict future RWI values. Results indicate that sapling trees RWI correlate with summer temperatures, but does not strongly correlate with precipitation. It is predicted that when compared to mature trees, saplings will not have a consistent response in how they are impacted by climate change due to the differences in factors that influence the establishment of trees