Fig. 5

Marginal response curves for the four variables included in the productivity model for current environmental conditions. Variables are ordered by their contribution to the model (importance score). LIT_dlo, lithostratigraphy; Geo_units, geology strata; R, probability occurrence of R horizon within 0–200 cm (%), isothermality (BIO3, °C). The mean (black line) and standard deviation (grey area) of the probability presence. The prediction value of site index is shown as a function of each variable while all other variables are held at their median values for locations where Atlantic populations of maritime pine is present. Note: supplementary Tables S1 and S2 include the significance of the numerical codes shown in the two first graphs