2.3.1 Climate data
Monthly and annual climatic data (annual precipitation and MAT) were collected from 1979 to 2017 at 65 weather stations located within our study region. We used Kriging interpolation method to interpolate meteorological data with a spatial resolution of 1 km×1 km and regionalize the various variables at different scales. Further interpolations were conducted to adjust the temperature to the respective mean plot elevation (Piao et al., 2011). We used this approach to calculate the mean value of the MAT and annual precipitation from 1979 to 2017 for each plot. And then, we used linear regression model to analysis the MAT and annual precipitation change over time (see Fig S2).