Mineral composition of eucalyptus bark and wood as a function of sample height and gypsum application

Whether gypsum application changes mineral composition of Eucalyptus urograndis bark and wood along a tree height gradient is uncertain. Therefore, an experiment was established to examine three rates of broadcasted gypsum (1.2, 4.8, and 9.6 Mg ha-1; control); applied before planting. Three years after application, discs were collected to obtain bark and wood chemical composition from the tree base and at 25, 50, 75, and 100% of total height. Results shows that calcium (Ca), iron (Fe), aluminum (Al), and manganese (Mn) can accumulate in wood at the tree base, while potassium (K), sulfur (S), and phosphorus (P) tend to accumulate in the upper portions of trees. Gypsum application increased concentrations of Ca, S, and P in wood; Ca, S, P and copper (Cu) in bark; and decreased Mn in bark and wood. Findings suggest that high gypsum rates increased exportation of Ca, S and P by wood. Additionally, to accurately estimate nutrient exportation it is important to sample at multiple height positions along the tree trunk.