The spatial variation of pH in the mor layer of some coniferous forest stands in Northern Sweden

Abstract

The spatial pH‐variation is shown to be slightly decreasing when comparing different coniferous stands in northern Sweden with a 200 m² respectively a 2 m² sample plot within a stand. The result indicates that the pH‐variation in the mor layer to a great extent is to be found in a plot <2 m². The hypothesis of Hesselman (1926) and Bergholm et al. (1985) that few samples should be enough for a reliable pH‐determination of a stand is questioned and critically discussed. The number of samples required to obtain a pH‐determination with an accepted accuracy is discussed. The spatial pH‐variation from the plots in the study suggests that approximately 12 samples are required to get a mean error of 2% at 95% confidence limits. But one should be aware of that, even with 12 samples, the difference between the highest and lowest value in a 2 m² plot will be about 0.6 pH‐units.

Key words:

• Picea abies
• Pinus silvestris
• soil
• pH
• spatial pH‐variation
• sampling
• North Sweden