The impact of juvenile tree species canopy on properties of new forest floor

Abstract

To keep forest soils fertile, forest practitioners plant mixed stands that are composed of both economically efficient trees such as conifers and soil-improving broadleaves. This is a mandated practice in the Czech Republic. As the new forest grows, it creates a dense canopy. The canopy is a principal source of organic matter to the forest soil. The formation of new forest humus is particularly important in first-generation forests on the former agricultural soil. Former meadow is a suitable site for forest floor and soil investigation since forest-floor humus covering the surface of the soil is a completely new layer.  Both pure evergreen conifer and mixed treatments were planted in 2001. The experimental plot was established in order to investigate performance of tree species and restoration of forest-site conditions. We sampled dead-plant material and 0–10 cm topsoil to investigate their properties under the 10-year-old stands. We compared the treatments by descriptive statistics using both univariate and multivariate techniques. Dry mass (medians of weight) varied among the treatments from 11 to 19 Mg·ha<sup>–1</sup>. The forest floor nutrient concentrations appeared to be dependent on the presence of admixed deciduous tree species (sycamore maple, small-leaved linden and European larch) as these forest floors (EL1, EL2, NS3, SM) were higher in base cations and phosphorus compared to pure spruce (NS1, NS2) and pure Douglas fir (DF) treatments. The first axis of PCA ordination plot revealed 45% of total variability and showed a clear distinction between evergreen coniferous and mixed species treatments. Young plantations produced forest floors of different quality; however it was not reflected in the topsoil properties.