Temporal evolution of drought index (DI = P−ETo) calculated for the period beginning October (Italy) or April (Chile) of the previous year and ending with September (Italy) or March (Chile) of the current year, and used to select climatically contrasting years.

<p>It must be pointed out that the great heterogeneity of the local environment in these mountainous areas can contribute errors to estimated values of drought index.</p

Mean (+1 standard error) δ¹³C, Δ¹³C, δ¹⁸O, Ci, iWUE, and BAI of <i>Fagus sylvatica</i> and <i>Nothofagus</i> spp. during the 20^th century.

<p>Different letters indicate significantly different values between sites (P<0.05; post hoc Boferroni test, after ANCOVA analyses). Populations are listed from North to South (Northern Hemisphere) or South to North (Southern Hemisphere).</p

Relationships between BAI and DI, iWUE and DI, BAI and iWUE, BAI and Ca, iWUE and Ca.

<p>Sites are referred to by symbols in the legend: Pian del Cansiglio, Sasso Fratino, Val Cervara, and Montedimezzo (North-Central Italy); Gargano, Cilento, Aspromonte, and Sila (Southern Italy); Omora low, Omora high, Torres del Paine, Villarrica, and Chillan (Chile). Site and species details are reported in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113136#pone-0113136-t001" target="_blank">Table 1</a>. Regression coefficients are reported in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113136#pone-0113136-t002" target="_blank">Table 2</a>.</p

Trend analysis results (based on the Mann–Kendall test) for parameters reported in Fig. 1 and 2, expressed as negative or positive <i>S</i> values, indicating decreasing or increasing trend, respectively.

<p>The tau coefficient varies between −1 and 1, and values closer to unity imply increasing agreement between the rankings.</p><p>Trend analysis results (based on the Mann–Kendall test) for parameters reported in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113136#pone-0113136-g001" target="_blank">Fig. 1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113136#pone-0113136-g002" target="_blank">2</a>, expressed as negative or positive <i>S</i> values, indicating decreasing or increasing trend, respectively.</p

Regression coefficients of the relationships between variables as shown in Fig. 4.

<p>Regression coefficients of the relationships between variables as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113136#pone-0113136-g004" target="_blank">Fig. 4</a>.</p

Variation in mean <i>Fagus sylvatica</i> and <i>Nothofagus</i> spp. δ¹³C, Δ¹³C, δ¹⁸O, Ci, iWUE, and BAI.

<p>Symbols with the error bars (±1 standard error, n = 4) are means of individuals per site in 10-years total values (±1 standard error n = 4). Temporal trends of Ca and atmospheric δ¹³C are also reported (dashed lines). Sites are referred to by symbols in the legend: Pian del Cansiglio, Sasso Fratino, Val Cervara, and Montedimezzo (North-Central Italy); Gargano, Cilento, Aspromonte, and Sila (Southern Italy); Omora low, Omora high, Torres del Paine, Villarrica, and Chillan (Chile). Site and species details are reported in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113136#pone-0113136-t001" target="_blank">Table 1</a>. Populations are listed from North to South (Northern Hemisphere) or South to North (Southern Hemisphere).</p

Relationships between δ¹⁸O and δ¹³C of cellulose for trees at Pian del Cansiglio, Sasso Fratino, Val Cervara, and Montedimezzo (North-Central Italy); Gargano, Cilento, Aspromonte, and Sila (Southern Italy); Omora low, Omora high, Torres del Paine, Villarrica, and Chillan (Chile).

<p>Populations are listed from North to South (Northern Hemisphere) or South to North (Southern Hemisphere). Symbols with the error bars (±1 standard error, n = 4) are mean values per each site. The regression equation and coefficient of correlation are also shown (P≤0.01). Site and species details are reported in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113136#pone-0113136-t001" target="_blank">Table 1</a>.</p

Location, tree species and main characteristics of the sampling sites (and coordinates of the meteorological CRU TS 3.1 data set), as well as mean annual temperature (T) and total annual precipitation (P) obtained from nearby meteorological station (30-year mean).

<p>Populations are listed from North to South (Northern Hemisphere) or South to North (Southern Hemisphere).</p><p>Location, tree species and main characteristics of the sampling sites (and coordinates of the meteorological CRU TS 3.1 data set), as well as mean annual temperature (T) and total annual precipitation (P) obtained from nearby meteorological station (30-year mean).</p

Cumulative average basal area for the three species.

<p>Full symbols represent the 50- year cumulative average basal area of <i>E</i>. <i>cylindricum</i> (a) and <i>T</i>. <i>scleroxylon</i> (b) and 20 years for <i>E</i>. <i>ivorense</i> (c). The continuous line represents the weighted best fit linear interpolation with the dashed lines defining the confidence interval of the fit (see text for details)</p

Ring width chronologies of <i>T</i>. <i>scleroxylon</i>.

<p>(a) Ring width chronologies of <i>T</i>. <i>scleroxylon</i> with mean chronology (black line) using raw data of average increment rates per tree. (b) Average ring width chronology (n = 25) with standard deviation (SD) of <i>T</i>. <i>scleroxylon</i> after detrending. The number of samples is reported.</p