Silver Fir Defoliation Likelihood Is Related to Negative Growth Trends and High Warming Sensitivity at Their Southernmost Distribution Limit

Figure 3

Regional standardized mean temperature (T), standardized precipitation index (SPI), standardized total precipitation minus evapotranspiration (P-ETP; difference between precipitation—P—and potential evapotranspiration—ETP), and standardized basal area increment chronologies of declining and nondeclining silver firs. Pearson correlation coefficients (𝑟) for the relationships between standardized basal area increment and the annual climatic variables are also displayed with their significance levels (*𝑃<0.05; **𝑃<0.01).