Effects of wood ash, vitality fertilizer and logging residues on needle and root chemistry in a young Norway spruce stand

Abstract

The nutrient status of a 6-year-old Norway spruce stand in south-west Sweden was examined 4 and 5 years after application of soil ameliorative treatments. In addition to control plots, three treatments were tested: granulated wood ash at 4150 kg dry weight (dw) ha⁻¹, a nitrogen-free, dolomite-based vitality fertilizer (SkogVital) at 2×1500 kg ha⁻¹ and the fine fraction of harvest residues (mostly needles) at 15,050 kg dw ha⁻¹. The treatments had no short-term effect on height increment. Nitrogen (N) was probably the growth-limiting element, but phosphorus (P) and potassium (K) were also in suboptimum supply. The vitality fertilizer increased the foliar concentration (or the element/N ratio) of P, calcium (Ca) and zinc, while ash application increased the foliar Ca/N ratio. The vitality fertilizer also increased magnesium and Ca concentrations in roots and decreased aluminium concentrations, whereas logging residues and wood ash only increased manganese concentrations in roots. Thus, the vitality fertilizer had a more marked effect on tree nutrient status than the granulated wood ash.

Keywords:

• Fine roots
• mineral nutrients
• needle analysis
• Norway spruce
• soil amelioration
• wood ash

We thank Ulf Johansson, director of the Tönnersjöheden Experimental Forest, and his staff for establishing and maintaining the experiment, as well as carrying out the sampling. Chemical analyses were carried out in the Miljöforskningslaboratoriet, SUAS, Umeå. We are grateful to Aili Irene Colbing, Kerstin Ahlström, Berit Solbreck and Thomas Grönqvist for laboratory assistance. We thank Gunnar Thelin and anonymous reviewers for constructive comments on earlier versions of the manuscript. Mary McAfee corrected the English. Financial support was provided by the Swedish National Energy Administration.