Beech Forest Density Control on the Dominant Water Flow Types in Andic Soils

Abstract

Silvicultural operations increasingly aim to achieve desired water‐related ecological services of forests and forest soils. Therefore, the effects of forest stand density, site, and soil depth on the water flow types were studied by conducting dye tracer experiments in two montane beech (Fagus sylvatica L.) forests located in the Western Carpathian Volcanic Range, Central Slovakia. Prevalent flow types were identified under usual weather conditions. Brilliant Blue FCF dye tracer was periodically applied in powder form on 1‐m2 plots in forest stands with natural and reduced stand densities, as well as in clear‐cuts. When cumulative precipitation reached approximately 100 mm, soil pits were excavated. The dye patterns on the exposed profiles were photographed, and dye coverage, relative dye concentration, and stain widths were determined at various soil depths using image analysis. These patterns were used to discriminate two flow types. Continuous vertical dye plumes were interpreted as an indicator of surface‐controlled flow type, which includes heterogeneous infiltration and macropore flow. The matrix‐controlled flow type includes both homogeneous and heterogeneous matrix flow, as well as fingering. The log‐linear analysis revealed that forest stand density and soil depth were significantly related to the soil water flow type. Preferential flow resulted from heterogeneous infiltration and fingering in the clear‐cuts, from heterogeneous infiltration in the natural stands, and from macropore flow in the shelterwood stands. Distinct humus forms and skeleton fraction played a crucial role for various flow patterns observed in these beech stands.