Spatial variability of forest foor and topsoil thicknesses and their relation to topography and forest stand characteristics in managed forests of Norway spruce and European beech
Abstract
Soils play a signifcant role in climate regulation, especially due to soil organic carbon (SOC). The SOC pool is therefore modeled for various environments, and forest foor and topsoil thicknesses are important parameters for most of these models as they store most of the SOC.
However, the forest foor and topsoil thicknesses show high spatial variability which is a result of multiple factors which are not agreed upon among scientists. Out of these factors, we choose topography parameters (elevation, slope, and topography wetness index) and forest stand characteristics (stand age, dominant tree species, and forest foor cover), and soil moisture, and we analyzed their relationship to the forest foor and topsoil thicknesses.
The study was performed in a managed submontaneous forest in Central Europe dominated by Picea abies (L.) Karsten with small patches of Fagus sylvatica L. or other species. The thicknesses of the O horizons (Oi, Oe, Oa) and topsoil were measured at 221 sampling pits.
Geographically weighted regression showed that the spatial variability of the overall forest foor plus topsoil thickness (OA) is responsible for 8% of its variability. The thickness of the OA is the most strongly controlled by forest foor cover explaining approximately 6% of its variability and soil moisture explaining 2-6% of the variability.
The Oi+Oe horizon thickness is controlled only by forest foor cover explaining 10.7% of its variability, and the thickness of Oa+A horizon can be explained mainly by soil moisture in mineral horizon explaining 9% of the variability.