Inorganic elements in tree compartments of Picea abies - Concentrations versus stem diameter in wood and bark and concentrations in needles and branches

Concentrations of elements in stem wood, bark, branches and needles, and empirical functions for the variation in concentrations with stem diameter in bark and stem wood for Norway spruce (Picea abies) are presented. The samples were collected from 36 trees from nine different localities from the central and southern parts of Sweden. Disc samples were taken from the trunk of each tree at five heights and the diameters of each disc were measured. Living branches and their needles from each tree were collected and separated and each fraction was treated as one bulk sample. Concentrations of 23 elements were analysed by ICP-MS. The needles contained the highest concentrations of most of the elements, followed by branches, bark and wood in that order. The element concentrations for Ba, Cd and Pb in wood and Ba, Ca, Cd, Co, Mn, Sr and Zn in bark were significantly positively correlated with diameter, while negative correlations were found for Cu, Fe, K, Mg and P in wood and Cr, Cu, Fe, K, Na, Ni and P in bark. Due to high variation in element concentrations between single trees, the functions should be used at the stand level rather than for single trees. Calculations of export of elements through removal of logging residues using the diameter-based functions were compared with calculations using average concentrations of elements in the stem and bark. The average concentration method resulted in an underestimation of 26%, 17%, 30%, 22% and 51% for Cu, Fe, K, Mg and P, respectively, and an overestimation of 29%, 24% and 29% for Ba, Cd and Pb, respectively. (C) 2007 Published by Elsevier Ltd