RELATIONSHIPS BETWEEN ENVIRONMENTAL-FACTORS AND HEIGHT GROWTH AND YIELD OF NORWAY SPRUCE STANDS - A FACTOR-ANALYTIC APPROACH

Soil samples were taken from 148 experimental plots and subjected to analysis of 34 morphological, physical and chemical properties. At the same time, eight climatic and topographic characteristics were recorded. For each plot the values of top height and yield were available. The relationships between the soil properties and climatic/topographic characteristics were studied separately, for both sets of variables, by means of factor analysis. The orthogonal varimax prerotation and the oblique promax rotation were used. For soil characteristics, five common factors were identified, explaining 90 per cent of the total variance, related to soil acidity, water retention, humus content, nutrients and soil texture. For climatic/topographic characteristics, three factors were found, related to temperature, precipitation and terrain formation, explaining 85 per cent of variance. The relationships between the identified factors and height growth and/or yield were quantified by polynomial regression analysis. Appropriate regression models were found for all factors except the factor 'nutrients'. Most regressions proved to be non-linear. The applicability of the factor analysis for determining the environmental factors is discussed.