RETENTION OR LOSS OF NITROGEN IN FOREST WETLANDS

LARS LUNDIN

There are diverging opinions on nitrogen retention in wetlands. In southern Sweden, wetlands contribute to limit nitrogen leaching. In forest wetlands in central and northern Sweden there are only indications on small or no retention effects. Wetland types as well as the nitrogen load vary. Outflow of nitrogen from forested watersheds, including considerable wetland areas, is larger than nitrogen outflow from watersheds dominated by drained mineral soils. On forested wetlands, there is a nitrogen uptake by the trees that might reduce leaching more than what could be achieved in treeless wetlands.