Arnold Arnoldussen

Element levels in birch and spruce wood ashes — green energy?

Production of wood ash has increased strongly in the last ten years due to the increasing popularity of renewable and CO(2)-neutral heat and energy production via wood burning. Wood ashes are rich in many essential plant nutrients. In addition they are alkaline. The idea of using the waste ash as fertiliser in forests is appealing. However, wood is also known for its ability to strongly enrich certain heavy metals from the underlying soils, e.g. Cd, without any anthropogenic input. Concentrations of 26 chemical elements (Ag, As, Au, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sr, Ti, and Zn) in 40 samples each of birch and spruce wood ashes collected along a 120 km long transect in southern Norway are reported. The observed maximum concentrations are 1.3 wt.% Pb, 4.4 wt.% Zn and 203 mg/kg Cd in birch wood ashes. Wood ashes can thus contain very high heavy metal concentrations. Spreading wood ashes in a forest is a major anthropogenic interference with the natural biogeochemical cycles. As with the use of sewage sludge in agriculture the use of wood ashes in forests clearly needs regulation.

Development and Challenges of the Anthroscapes in the Clay Soil District of Eastern Norway

Anthroscapes are dealing with the adaption of land management to soil- and terrain conditions. Under human influence specific soil and landscape conditions can develop over long periods of time. Due to the low population pressure and historical developments other systems of Anthroscapes could develop in Norway.