[The Danish forest condition survey: Results of survey in 1997]

acid deposition air pollution analyse de sol anillo de crecimiento bosques cerne chute des feuilles danemark denmark dinamarca encuestas forestales enfermedades de las plantas forest land forest surveys forests growth rings insecte nuisible leaf fall maladie des plantes nitrogen oxides oxyde d'azote pest insects plant diseases public ownership soil testing terrain forestier tierras forestales weather