Contribution to the problem of breeding of cultivated poplars in the area of Vychodoslovenske steelworks [Slovak Republic]

altura carga contaminante charge polluante contaminantes industriales crecimiento croissance diameter diametro environmental factors espacement espaciamiento facteur du milieu factores ambientales genotipos genotypes growth growth rate hauteur height industrial pollutants lowland polluant industriel pollutant load populus slovak republic soil types spacing taux de croissance tierras bajas type de sol variedades varieties