Dendroclimatic analysis of Betula ermanii forests at their upper limit of distribution in Changbai Mountain, Northeast China

In order to detect the effects of climate change on Erman's birch (Betula ermanii Charm.), we examined radial growth—climate relationships of Erman's birch forests at their upper limit of distribution in Changbai Mountain, Northeast China. Thirty Erman's birch trees from six stands were sampled at an elevation of about 1950 m a.s.l. Correlation and response function coefficients indicated that radial growth of Erman's birch was positively influenced by previous August, October and current February temperature, and previous winter, and current March, June and September precipitation. In addition, radial growth showed a negative relationship to previous August and current June sunshine ratio. Precipitation and temperatures in annualization periods also positively affected the radial growth of Erman's birch. Regression analyses indicated that precipitation explained more variation in radial growth than minimum temperature. Together, these results suggested that climate affected radial growth of Erman's birch through altering soil water availability. Therefore, the radial growth of Erman's birch at the tree line in Changbai Mountain could not be predicted by temperature alone even under a scenario of global warming.