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 (mol 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 (mol 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 (mol 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 mol 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.