Abstract: The seasonal growth and biomass of seedling-sprouts from five different clonecuttings are stueled in detail in this paper.The height, diameter and volume growthof different etone trees are compared.It was found that the I-69 poplar retainned the highest dry matter production, then followed by the I-72 and I-214 poplars,with the "blanc de garonne" being thelowest.It is obvious that all of these modern clones are characterized by fastgrowth. The height, diameter and volume growth measured five years after planting averaged 18-20M. , 30-40 cm. and 0.52-0.60M3 per tree respectirely. Their resistance to Melampsora rust and Marssonia diseases was apprsaciably high.