Stocks of Forest Litter in the Oak Forests of the Chernobyl Nuclear Power Plant Exclusion Zone

Forest litter (FL) plays the most important role in the migration of radioactive substances in biogeocenoses of the Chernobyl nuclear power plant exclusion zone. There is to date no information on the characteristics of litter in oak forests in this area. The aim of this study is to identify the main indicators of FL and factors influencing its accumulation in stands of the most common oak forests types (Quercetum oxalidosum, Q. aegopodiosum, Q. subalveto-fluvialis, and Q. graminoso-fluvialis), occupying 61.1% of the oak forest formation in Belarusian sector of the Chernobyl NPP exclusion zone. It was found that the average values of their characteristics by forest types, obtained with an accuracy of 3.1–8.2%, vary in extremely narrow ranges: thickness 1.7–2.9 cm, stocks 1.6–2.7 kg m–2, and addition density 0.08–0.11 g cm–3. The FL is loose, in comparison with other regions of Eastern Europe; within the boundaries of the natural range of oak they are, as a rule, thinner and with a smaller mortmass stock. Their total stock in the Chernobyl exclusion zone is about 200 000 t of absolutely dry matter. The thickness and stock of FL mortmass are very heterogeneous. They are characterized by high fluctuations in individual values and in average coefficients of variation (40–56%). The average values of thickness and stock differ significantly between most types of forests. These indicators are closely related to each other (r = 0.76). The density of the FL, despite the high coefficients of variation of average values (27–71%), is rather homogeneous. The formation of FLs and their mortmass accumulation in the oak forests is determined by the cumulative effect of weather and climatic conditions, landscape, soil fertility and moisture, and the quantity of fallen off vegetable parts with the leading role of soil moisture supply.