Chemical analyses of mineral soils, O horizons and tree foliage
The mineral soil, O horizon and foliage samples were analyzed for total carbon and total nitrogen concentration using LECO TruMac® CNS analyzer. The inorganic C content in mineral soil samples was calculated based on the carbonate content measured with the gas-volumetric Scheibler method. The organic C (Corg) content was then calculated as a difference between the total C and the inorganic C. Total phosphorus (Pt) was determined colorimetrically by the molybdate blue method from aqua regia extracts by Varian CARY 300 Conc UV–Visible Spectrophotometer.
The texture of mineral soil samples was determined by hydrometer using Bouyoucos method. The pH of the samples was measured in H2O (pHH2O) and 1 M KCl solution (pHKCl) (soil/liquid ratio 1:5, w/v) at 20° C using a digital pH meter (CPC-411, ELMETRON). Data on the texture and pH of the studied soils are presented in supplementary material (Table S1).