Nutrient cycling in two continuous cover scenarios for forest conversion of pine plantations on sandy soil. I. Nutrient cycling via aboveground tree biomass

摘要

Conversion of coniferous pine plantations into mixed-species forests on sandy soils is an important concern for forest and nature management in Europe. However, little is know of the effect of the applied sylvicultural strategy on biogeochemical cycling throughout the conversion process. This study examined the aboveground biomass production and nutrient (N, P, K, Ca, and Mg) cycling in terms of litterfall, immobilization in stems and branches, canopy exchange, and yearly root uptake in two scenarios of continuous cover forestry a decade after the first intervention for converting a homogeneous Scots pine (Pinus sylvestris L.) forest. Four regeneration types were studied: silver birch (Betula pendula L.) and pine after a shelterwood cutting and birch and pine after a group cutting. In conclusion, it can be stated that both the tree species and the conversion scenario influence the circulation of nutrients through the forest ecosystem: cycling of N, P, and K is determined by the tree species as well as the conversion scenario, whereas circulation of Ca and Mg is predominantly influenced by the type of conversion.