Nutrient fluxes via litterfall in silver birch (Betula pendula Roth) stands growing on post-arable soils

Abstract

The purpose of this study was to evaluate the importance of litterfall as a link in biogeochemical cycling of certain elements (C, N, P, K, Ca, Mg, Fe, Mn, Cu, and Zn) in silver birch stands growing on post-arable soils under temperate climatic conditions (Poland). The study covered three stands on sandy soils (21, 29, and 40 years old) and three on loamy soils (15, 33, and 41 years old). Litterfall was collected during 2020–2021 and analysed using standard procedures. Elemental contents were determined also in green leaves collected from the tree crowns in early summer to determine intensity of retranslocation. The total litterfall production varied from 2576 to 5293 kg ha−1, depending on the stand and year. These values are typical of temperate forests. Litterfall production was positively correlated with stand age. Leaves made up the major fraction, followed by twigs. Silver birch litterfall was generally rich in nutrients compared to many other tree species typical for temperate climatic zone. Nutrient fluxes to the soil were in the upper limits reported in the literature. It may partially be an effect of the post-arable history of these stands. Large fluxes of nutrients to the soil via litterfall are important in the context of the high nutritional demands of the studied tree species. This study also showed that silver birch strongly retranslocates N, P, and K from senescing leaves, whereas Ca, Mg, Fe, Mn, Cu, and Zn are accumulated in these organs.