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

Author(s)
Clemens Reimann, Rolf Tore Ottesen, Malin Andersson, Arnold Arnoldussen, Friedrich Koller, Peter Englmaier
Abstract

Production of wood ash has increased strongly in the last ten years due to the increasing popularity of renewable and CO2-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

Organisation(s)
Department of Lithospheric Research
External organisation(s)
Geological Survey of Norway, Norwegian Forest and Landscape Institute
Journal
Science of the Total Environment
Volume
393
Pages
191-197
No. of pages
7
ISSN
0048-9697
Publication date
2008
Peer reviewed
Yes
Austrian Fields of Science 2012
1060 Biology, 105904 Environmental research
Sustainable Development Goals
SDG 2 - Zero Hunger, SDG 7 - Affordable and Clean Energy
Portal url
https://ucrisportal.univie.ac.at/en/publications/54d31839-750e-4bc8-be36-aae328acde2e