Ozone exposure-response relationships for biomass and root/shoot ratio of beech (Fagus sylvatica), ash (Fraxinus excelsior), Norway spruce (Picea abies) and Scots pine (Pinus sylvestris). - Landolt,W..; Buhlmann,U..; Bleuler,P..; Bucher,J..B.. (Environmental Pollution, 2000)