Fig. 4

Relationship between tree mortality and climate variables such as a precipitation in January (Pre1) and b average annual maximum temperature in July (Tmax) for fir, oak, and birch. Tree mortality increased with the Tmax and Pre1 rising for fir and oak, respectively. Moreover, a U-shaped relationship was found for birch of Tmax and Pre1. The inflection values of Pre1 and Tmax for birch were 6.9 mm and 21.3 °C, respectively