[Ecoedaphic conditions of growth of spruce stands in Slovakia]

The influence of some site factors on the mean heights of Norway spruce stands in the age of 100 years (determined on the basis of the dominant height of the stand) was assessed on 148 experimental plots on the whole territory of Slovakia. The slope angle ranged between O and 35 degree, the altitude ranged from 430 to 1300 m a. s.l. All expositions and all slope positions were represented the soils were formed from different parent rocks. The variability of stand height was influenced more by the climatic and topographic factors than by soil factors. Among the first group of factors, the most signiftcant influence was observed in the altitude and the mean annual temperature. The highest stands were occurred in the altitude 650 m and by the mean annual temperature 6.5 degree C. The influence of the slope angle, expositions and slope positions was not found. For the soil characteristics, the strongest correlations were recorded in the depth of the humus layer. With the increased depth the site index also increase, at the depth of 2.8 cm the mean height of stands are the greatest, with additional increasing of humus layer the height of stand decrease. The significant correlation was also found with the proportion of skeleton, the soil acidity and humus content. The optimum soils from the point of view of Norway spruce height growth are those with soil pH/H2O = 5.16 (pH/ KCI = 4.42) in A-horizon and pH/H2O = 5.60 (pH/KCI = 4.70) in the depth of soil 15-20 cm, low skeleton and humus content. No dependence of the stand height was occurred from the soil structure and bulk density, however, the general physical state, which represents the expression of the whole complex of soil properties (structure, texture, consistent), exhibited a clear influence on the height growth. We have neither found a significant relation between the stand height and the contents of phosphorus, potassium and calcium. On the other side, a comparatively strong correlation was observed in magnesium and nitrogen. There are also differences in stand height among stands, growing on the soils belonging to different soil types. The rendzinas, podzols and dystric cambisols proved to be the least suitable for the point of view of the height growth of Norway spruce.