Figure Legends
Fig.
1 (a) Annual mean temperature, (b) annual precipitation of the growing
season (June to September), and (c) the De Martonne Index (DMI)
reflecting environmental aridity of the study area for the period of
1970-2019. The solid line in panel a shows a significant trend of
temperature increase, the dashed lines in panel b, c show the average of
annual growing seasonal precipitation and DMI for 1970-2019, and the
shaded area in panel c indicates the -1.5 times standard deviation of
DMI. Data were from Zhangwu meteorological station located about 31 km
from the study site.
Fig. 2 The change of cumulative basal area (CBA) with tree
cambial age for each studied conifer species. The dashed vertical line
marks the age of 15 years and the number in the upper right corner of
each panel shows the CBA value at a cambial age of 15 years
(CBA15) for each species. Species name abbreviations are
as shown in Table 1.
Fig. 3 Standardized tree-ring width chronologies (red lines) of
the seven studied tree species. The blue line in each of the left panels
shows the number of cores in specific years. The panels on the right
show standardized tree-ring width indices during, before and after the
2015 drought event. Species name abbreviations are as shown in Table 1.
Fig. 4 (a) Net photosynthetic rate on per leaf dry mass basis
(A m) and (b) sapwood-specific hydraulic
conductivity (K s, gray bars) and leaf-specific
hydraulic conductivity (K l, black bars) of the
seven studied conifer species. Error bars show 1SE (n = 8).
Species name abbreviations are as shown in Table 1.
Results
of one-way analyses of variance are shown in each panel.
Fig. 5 (a) hydraulic safety margin (HSM), (b) wood density (WD)
and leaf osmotic potential at zero turgor (π 0).
Error bars show 1SE (n = 18-24 for WD, n = 8-10 for HSM
and π 0). Species name abbreviations are as
shown in Table 1. Results of one-way analyses of variance are shown in
each panel.
Fig. 6 Correlations between tree drought resistance index (RT),
resilience index (RS) and (a, d) wood density (WD), (b, e) hydraulic
safety margin (HSM) and (c, f) leaf osmotic potential at full turgor
(π 0). Horizontal error bars show ± 1SE
(n = 18-24 for WD, n = 8-10 forπ 0). Symbols are as defined as in Table 1.
Fig. 7 Correlations between tree drought resistance index (RT),
resilience index (RS) and (a, c) leaf-specific hydraulic conductivity
(K s) and (b, d) net photosynthetic rate on per
leaf dry mass (A m). Horizontal error bars show ±
1SE for K s and A m,
respectively (n = 8). Symbols are as defined as in Table 1.
Fig. 8 Correlation between the cumulative basal area at cambial
age of 15 years (CBA15) and mean sensitivity from
tree-ring analysis across the seven studied conifer species. Symbols are
as defined in Table 1.