Some Results of Stationary Sample Plot for Intensive Monitoring of Forest Ecosystems in Vitinya Area Ludmila Malinova, Kameliya Petrova University of Forestry 10 Kl. Ohridski Blvd., Sofia, Bulgaria Corresponding Author: Ludmila Malinova, e-mail: ludmila_malinova@yahoo.com Received: 11 March 2020 Accepted: 10 May 2020 Abstract Results are presented for the chemical composition of the forest litterfall and lysimetric waters of Cambisols from the intensive monitoring stationary sample plot of the forest ecosystems. Litterfall (litter biomass fraction) had fallen on the soil surface with acid reaction, which in the period 2011 - 2018 varied from 5.1 to 5.4. The established contents of calcium (6.9 mg.g -1 ), magnesium (0.52 mg.g -1 ), potassium (3.58 mg.g -1 ), nitrogen (7.28 mg.g - 1 ) and phosphorus (0.55 mg.g -1 ) were low and those of manganese (1754 µg.g -1 ), iron (185 µg.g -1 ), copper (11 µg.g -1 ) and zinc (36 µg.g -1 ) were high. The lysimetric waters in the surface horizon were very strongly acidic – pH H2O = 4.6. The amounts of all the tested parameters in them were very low – dissolved organic matter (8.0 mg.dm 3 ), potassium (2.6 mg.dm 3 ), calcium (5.7 mg.dm 3 ) and others. Only the content of manganese was increased, which in some years exceeded the maximum value pointed in the literature for the European forests. It is assumed that degradation processes take place in the mineral part of the soil which lead to its impoverishment of macro and microelements. Key words: litterfall, lysimetric waters, common beech, Сambisols Introduction In the forest ecosystems, nutrients make internal circulations along the 'entrance and exit' paths in them. The entrance is implemented through the litterfall, wet and dry depositions, stemflow, and the exit - through cuttings, lysimetric waters, etc. (Smidt et al., 2012). Their behavior inside the soil depending on its reaction, adsorption surfaces, and others. The results of the impact of anthropogenic activity are evaluated by the displacement of the basic cations from the litter (L) and the soil, the occurrence of calcium and magnesium deficiency in the leaves of tree species, and others (Kiikkilä, 2003). The main sources of nutrients for the soil are litterfall and weathering processes. Litterfall becomes very important when in the soil-plant system the biological cycle dominates over the geochemical one. According to Legout et al. (2014) in rich soils, nutrient amounts are result of weathering processes, i.e. from the dominance of the geochemical circle. However, the intensity of weathering is determined by the climatic conditions, and for the mountainous territories in the country they are most often characterized as “harsh”. Bulgarian Journal of Soil Science® 2020 Volume 5. Issue 2. www.bsss.bg 101