Biometric sample characterization. Part 1: the influence of the infestation with insects to element concentrations in spruce needles

adelges air pollution alemania allemagne arbre forestier biological indicators cadmio cadmium calcio calcium chemical composition composition chimique feuille foliage forest pests forest trees germany heavy metals hojas indicator organisms indicator plants infestation insecte nuisible lead leaves metales pesados monitoring organisme indicateur organismos indicadores pest insects pests of plants picea abies plagas de plantas plagas forestales plantas indicadoras plante indicatrice plomb plomo potasio potassium ravageur des plantes seasonal variation vigilancia