Fig. 1
From: Phosphorus nutrition of beech (Fagus sylvatica L.) is decreasing in Europe
Foliar P levels and trends on 79 beech plots in Europe. Foliar P concentrations (plot median over the whole 20-year period) were in the normal or the latent deficiency range on 62 plots (circles foliar P ≥ 1.07 mg g−1) according to the classification system of van den Burg (Mellert and Göttlein 2012) and in the deficiency range on 17 plots (squares foliar P < 1.07 mg g−1). Foliar P concentrations decreased (downwarded triangles) on 65 plots and increased (upwarded triangles) on 14 plots during the 20-year observation period (black triangles p < 0.05; gray triangles 0.05 < p < 0.1; white triangles p>0.1