Beschreibung:
<jats:p> The availability of phosphorus (P) and potassium (K) commonly limits tree growth on drained peatlands. The nutritional status and volume growth of Scots pine (Pinus sylvestris L.) after varying doses of wood ash fertilization were investigated in seven field experiments located on deep-peated sites in Finland between latitudes 63°N and 67°N. Needle samples were taken 1420 years after fertilization and trees measured 15 years after fertilization. Annual growth rates and differences in foliar nutrients were analyzed with a two-way ANOVA model. A regression model was used in the analysis of periodic relative volume growth. High doses of wood ash (100265 kg P·ha<jats:sup>1</jats:sup>, 225450 kg K·ha<jats:sup>1</jats:sup>) resulted in greater changes in foliar nutrient concentrations and in a stronger growth response than low doses (550 kg P·ha<jats:sup>1</jats:sup>, 14210 kg K·ha<jats:sup>1</jats:sup>). Significant increases in needle mass and concentrations of P, K, and B were observed in the ash-fertilized stands, with a good status for these elements 20 years after fertilization. Depending on the ash dose, the mean annual volume growth was 0.51.4 m<jats:sup>3</jats:sup>·ha<jats:sup>1</jats:sup> higher than in the control plots during the 15 year postfertilization period. </jats:p>