Phase I: Competition studies on ectomycorrhizal fungi in artificial substrates and natural soils under the influence of nitrogen and elevated concentrations of atmospheric CO2

Phase II: Impact of elevated atmospheric concentrations of CO2 and of N-fertilization on abundance and extramatrical mycelia of ectomycorrhizae of Norway spruce (Picea abies) and beech (Fagus sylvatica)

Phase III: Biomass and space occupation of ectomycorrhizal mycelia under elevated ozone and carbon dioxide

Phase IV: Effects of elevated tropospheric ozone on below-ground space occupation and space exploitation of ectomycorrhizal mycelia