Soluble N compounds in trees exposed to high loads of N: a comparison of spruce (Picea abies) and beech (Fagus sylvatica) grown under field conditions. - Schneider,S..; Geßler,A..; Weber,P..; v. Sengbusch,D..; Hanemann,U..; Rennenberg,H.. (New Phytologist, 1996)