Additional file 3. Stress-strain curve (black, open circles) between point measurements of xylem water potential (MPa) and xylem shrinkage (Δd/di, µm mm−1) of Fraxinus excelsior L. during dehydration. The segmented-linear regression with two breakpoints (black and red dashed line) divided the dataset in three linear regressions with their own equation and R2 (black, red, and grey) from which continuous xylem water potential was calculated.