Fig. 1. Location and basic characteristics of the study plots.

Fig. 2. Total defoliation, proportion of secondary shoots, and categories of stress response. The bubble size represents the number of trees with the given values of the total defoliation and proportion of secondary shoots – this is continuum from the smallest bubble representing one tree to the biggest bubble representing 15 trees.

Fig. 3. (a) Tree-ring width (TRW) chronologies of the three stress response categories. (b) Basic characteristics of the three TRW chronologies: MSL – mean segment length; AGR – average growth rate (mm); SD – standard deviation; MS – mean sensitivity; AC1 – first order autocorrelation; Rbar – inter-series correlation; EPS – expressed population signal. (c) Coherence of the TRW chronologies over the common period (1963–2012) expressed on the left down side by THO (THO: T-value after Hollstein (1980)) and on the right upper side by GL (Gleichläufigkeit [“coefficient of agreement”] (Eckstein and Bauch 1969). (d) TRW chronology of all the trees, number of TRW series and negative pointer years.

Fig. 4. Means of the Pearson correlations between growth indices and the monthly climate variables temperature (white bar), precipitation (black bar). * indicate significant level (p < 0.05).

Fig. 5. April–May temperature and precipitation and their effects on radial growth. (a) April–May temperature given as absolute deviation relative to the climate normal period 1961–1990 (°C); (b) April–May precipitation given as absolute deviation relative to the climate normal period 1961–1990 (mm); (c) 21-year moving correlation windows: between tree-ring width index (TRWI) and April–May precipitation (grey); between TRWI and April–May temperature (black). The dotted horizontal lines indicate significant level (p < 0.05).

Fig. 6. Spatial correlations between tree-ring width indices and April–May precipitation from Climate Research Unit Time Series CRU TS3.23 (Harris et al. 2013) for the periods 1915–1963 and 1964–2012. View larger in new window/tab