Effects of environmental stress on forest crown condition in Europe. Part IV: statistical analysis of relationships

acid deposition air pollution altitud altitude atmosfera atmosphere climatic factors defoliation dioxyde de soufre drought environmental factors environmental impact europa europe facteur climatique facteur du milieu factores ambientales fagus sylvatica forest decline forest health geographical distribution impact sur l'environnement impacto ambiental marchitez del bosque monitoring nitrogen oxides oxyde d'azote ozone ozono picea abies pinus sylvestris quercus ilex quercus petraea quercus robur sanidad de los bosques site factors statistical methods sulfate sulphur dioxide vigilancia