Nutrient concentrations in stumps and coarse roots of Norway spruce, Scots pine and silver birch in Sweden, Finland and Denmark

The objective of this study was to evaluate the concentrations of nutrients in stumps and coarse roots in Norway spruce, Scots pine and silver birch in Sweden, Finland and Denmark, and to assess how nutrient concentrations vary with site characteristics, stand age and root size. Concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sodium (Na) in spruce, pine and birch stumps were assessed in eight sites across Scandinavia. Nutrient concentrations were higher in birch than in spruce and pine. In Sweden and Finland, the nutrient concentrations were generally higher at the southern sites than at the sites located in the northern part of the countries, except for P. For all nutrients, concentrations were significantly higher in the bark of the stump and roots than in the wood. Furthermore, nutrient concentrations increased significantly with decreasing root diameter. This study did not demonstrate any correlations with stand age. Further studies are needed to provide a broader picture of how the stump nutrient contents vary with site characteristics and forest management practices to provide a better foundation for nutrient balance calculations when setting up recommendations for stump removal. (C) 2012 Elsevier B.V. All rights reserved.