Restoration of forest soil and vegetation 15 years after landslides in a lower zone of mountains in temperate climates

The study analysed the variability of physical, chemical and biological properties of soil cover recovering fifteen years after a landslide. The soil properties were studied on a regular grid of points, which covered the entire area of the landslide of 0.50 ha. In 23 soil samples pH, sorption properties, total carbon and nitrogen content, microbial biomass carbon and nitrogen, activity of dehydrogenases and β-glucosidase, particle size and distribution and water resistance of soil aggregates were determined. Apart from detailed soil characteristics, in the test points the development of vegetation, its species composition, cover in each layer and tree species biomass were examined. On the basis of the level of soil cover with vegetation, canopy interception was calculated. It was found, that the landslide area is characterised by a stronger diversification of physical, chemical and biological properties in comparison to soils of the neighbouring forest stands (control points). As far as physical properties are concerned, the landslide area is characterised by a strongly diversified of clay fraction, level of soil aggregate development and their water resistance. The diversification of the physical properties is linked to a different accumulation of the organic substance and biochemical activity of the restoring soil cover. Locations with the highest abundance of clay fraction located in the upper part of the landslide niche and the lowest, edge portion of the landslide, are at the same time characterised by a lack of organic matter and low activity of soil enzymes. Contrary to those, the landslide fragments, which contain higher content of organic carbon, are characterised by a lower abundance of fine fractions and higher enzymatic activity. It was determined, that the soil recovery level determines the intensity of plant cover development, which in turn determines the correct level of interception while at the same time ensuring protection of the forming soil against the destructive effect of water erosion.