Mineral nutrients in leaves and bast of pedunculate oak (Quercus Robur L.) at different states of defoliation

Adult oaks (age> 135a) with different grade of defoliation were investigated for their mineral nutrient contents in leaves and bast. In the leaves of the trees with a defoliation of more than 60 % lower concentrations of almost all nutrients were found. No differences were found between defoliation class 1 (defoliation ≤ 25 %) and defoliation class 2 (defoliation ≤ 45 %). In all defoliation classes the mineral nutrient contents are in the normal range except the contents of magnesium, which is in the range of deficiency in all defoliation classes. The mineral contents in bast showed high concentrations of cadmium, manganese zinc, and aluminum in dead trees, and in the case of cadmium, in the trees of defoliation class 3 (defoliation ≥ 60 %). In the bast also no differences between defoliation class 1 and defoliation class 2 were found.