Mixed forestsClimateBiological interactionsForest managementNational Forest Inventory dataModelingPINUS-SYLVESTRIS L.FAGUS-SYLVATICA L.QUERCUS-ROBUR L.DIVERSITY-PRODUCTIVITY RELATIONSHIPSINTER-SPECIFIC COMPETITIONPETRAEA MATT. LIEBL.SCOTS PINEEUROPEAN BEECHSPECIES STANDSSTRUCTURAL HETEROGENEITY