关键词: 寒冷半干旱区, 杨树良种无性系, 欧美杨, 美洲黑杨

Abstract: There is a large area suitable for high yield plantation of poplar in the cold semi-arid area in North China. But the wide utilization of good clones of P. euramericana and P. deltoides introduced in this area is restricted by the dry and cold climate. We have recently introduced 45 poplar clones from the high latitudes of Europe and America in order to bring the potential ability of this land into full play.We have selected 4 clones of P. eurmericana and 1 clone of P. deltoides through isolated raising seedlings, disease-resistant and coldresistant selection, as well as cluster analysis of growth figures of these clones. The average tree height of the selected clones is 14.5—16.8m in the 6-year-old plantation, the average DBH, 19. 5—22. 9cm, the average volume per tree, 0.1956—0.3126m, and the form figureof the stem, 0.4476—0.4650. The average volume increment per hectare per year of these clones is 46.3%—134.2% higher than that of control cultivar, P. Beijingensis.The yields level of poplar plantation in this area will be increased in a large degree as a result of the extension of these cold-resistant and fast growing clones.

Key words: Cold semi-arid area, Good clones of poplars, Populus euramericana, P. deltoides