My research area is biogeochemical cycling of N, C and water with a main focus on N cycling in forests in particular N retention and nitrate leaching from forest under elevated N deposition (both in temperate and tropical forests). I have also worked with the stable 15N isotope to investigate the fate of deposition N in forest for this I have ongoing long-term (two decades) N addition experiments. My current research is on the controls of C sequestration in forest soils (N, tree species, forest age) in particular I try to resolve the effect of elevated N deposition on the soil C-sink. Other key research has been on monitoring methods and long-term manipulation experiments, forest water quality, afforestation impacts on soil and water, tree species effects on soil and water, climate change and mitigation, greenhouse gas exchange from forest soils which all contribute to the understanding and quantification of environmental services from forests.