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