Figure 2. (A) Dual isotope plot showing source water, xylem water (Cavitron) and bulk stem water (CVD) and their trend lines. (B) Distribution of the δD offset relative to source water. In (A), the black dashed line reflects the local meteoric water line (Lamontagne et al., in prep.), while the grey, dark blue and light blue lines reflect the source water, xylem water and bulk stem water lines, respectively. The boxplot shows the 10th, 25th, 50th, 75th and 90th percentiles of offset values.

Deuterium bias across tree species

We found significant differences in the CVD-induced δD bias among different tree species (Kruskal-Wallis; p<0.05) (Figure 3). Mean biases spanned a relatively broad range, from –19.3\($\textperthousand$\) (C. bella) to –9.1\($\textperthousand$\) (M. argentea). Pairwise comparisons indicated that most species had non-significant differences in mean δD bias, except for M. argentea which had significantly smaller δD biases than H. arborescens and C. bella (Dunn-Sidák; p<0.05) (Figure 3).