Growth and Carbon Isotopes of Mediterranean Trees Reveal Contrasting Responses to Increased

Growth and carbon isotopes of Mediterranean trees reveal contrasting responses to increased CO2 and drought

Elena Granda, Davi Rodrigo Rossatto, J. Julio Camarero, Jordi Voltas and Fernando Valladares

Electronic Supplementary Material (ESM1)

Table S1 Location of the study sites and their main characteristics (means ± SE).

Site / Latitude (N); Longitude (W) / Elevation / Aspect / Tree / dbh b / Age c / Density
(m a.s.l.) / species a / (cm) / (years) / (stems ha-1)
AR / 40º 46’ 39.88”; 2º 19’ 36.30” / 1060 / NW / PN; QF / 24.80 ± 0.53; 17.22 ± 0.29 / 62 ± 8; 46 ± 2 / 2400
HP / 40º 47’ 37.78”; 2º 17’ 08.93” / 848 / NE / QF / 20.36 ± 0.70 / 47 ± 1 / 900
QU / 40º 47’ 26.09”; 2º 17’ 56.79” / 884 / N-NW / PN / 33.08 ± 1.22 / 44 ± 2 / 2100
RS / 40º 51’ 09.43”; 2º 18’ 01.28” / 953 / SE / JT / 20.18 ± 0.32 / 44 ± 3 / 1400
TA / 40º 49’ 00.72”; 2º 12’ 35.90” / 1233 / NE / PN; JT / 27.95 ± 0.49; 17 ± 0.70 / 42 ± 3; 43 ± 3 / 2000
TI / 40º 48’ 16.22”; 2º 13’ 58.28” / 981 / S / PN / 28.78 ± 0.96 / 48 ± 1 / 2500

a Abbreviations of the species: QF, Quercus faginea; PN, Pinus nigra; JT, Juniperus thurifera.

b dbh: diameter at breast height (1.3 m).

c Age estimated at 1.3 m.

Table S2 Mean and standard deviations of variables used in the linear models, and correlation coefficients among these variables and with the year factor. P/PET, drought index; Ca, atmospheric CO2 concentration; iWUE, intrinsic water use efficiency; and BAI, basal area increment.

Mean / SD / Correlations
Year / P/PET / Ca / iWUE
Q. faginea
P/PET / 0.73 / 0.20 / -0.755
Ca (ppm) / 355.12 / 18.38 / 0.996 / -0.626
iWUE (mmol mol-1) / 90.92 / 8.89 / 0.658 / -0.515 / 0.668
BAI (cm2) / 2.72 / 1.30 / 0.003 / 0.154 / 0.009 / -0.068
P. nigra
P/PET / 0.73 / 0.19 / -0.756
Ca (ppm) / 354.66 / 17.67 / 0.996 / -0.624
iWUE (mmol mol-1) / 112.4 / 11.40 / 0.656 / -0.495 / 0.663
BAI (cm2) / 7.17 / 4.22 / 0.048 / 0.009 / 0.036 / -0.167
J. thurifera
P/PET / 0.71 / 0.17 / -0.686
Ca (ppm) / 357.04 / 17.35 / 0.996 / -0.532
iWUE (mmol mol-1) / 132.14 / 9.00 / 0.762 / -0.563 / 0.759
BAI (cm2) / 4.20 / 2.32 / 0.262 / -0.013 / 0.258 / -0.025

Fig. S1 Surface plots showing the predicted effect (see results from LMMs in Table 2a) of atmospheric CO2 concentrations (Ca, in ppm) and drought index (P/PET) on BAI (basal area increment, in cm2) for (a) Q. faginea and (b) P. nigra.

Fig. S2 Surface plots showing the predicted effect (see results from LMMs in Table 2b) of atmospheric CO2 concentrations (Ca, in ppm) and drought index (P/PET) on iWUE (intrinsic water use efficiency, in mmol mol-1) for (a) Q. faginea and (b) P. nigra. Note that the interaction P/PET * Ca is marginally significant in the case of P. nigra.