[The annual monitoring of forest health in Denmark 1993: results [Elatobium abietinum]]

air pollution arbre forestier betula bosques climatic factors danemark denmark dinamarca elatobium encuestas forestales especies facteur climatique fagus forest surveys forest trees forests fraxinus ips typographus lymantria monacha monitoring ozone ozono pests of plants picea abies picea sitchensis pinus plagas de plantas quercus ravageur des plantes species viabilidad viability vigilancia