Fig. 4: Graphical summary of climatic sensitivity traits presented at the population level in Mont-Laurier and Chibougamau common gardens.

Aboveground total carbon (TotalC) as of years a 1984, b 1995, and c 2015 expressed as a function of overall climate limitation on productivity. Negative values of climate limitations indicate that productivity is water limited; positive values indicate that productivity is temperature limited. Also plotted in a are averaged admixture proportions according to Q-values (K = 3) determined for each population (see Fig. 1d). The Pearson correlation r and two-sided P values at right of each panel indicate the goodness-of-fit between Chibougamau TotalC and climate limitation, for a given year (slopes are represented by dashed lines). No adjustment was made for multiple comparisons; the presence of spatial autocorrelation was taken into account⁸⁷. The relationship suggests that, in the northernmost garden, a shift of a population towards the water-limiting side of the x-axis takes place in parallel with a lower TotalC.