Comparison of Growth,Biomass and Photosynthesis among Six Poplar Clones in Cold Semi-arid Area of Northeast China

The seasonal growth of leaf area,height and diameter in six poplar clones(one-year old shoot/two-year old root)in 1993 was simulated with Richard function.The absolute growth rate,mean absolute growth rate,duration of growth and the point of inflexion were calculated using the parameters in the fitted functions respectively.There were significant differences among the six clones in growth rate,point of inflexion and duration of growth.A more than sixfold difference was found between the total biomass production of the best introduced clone Populus×euramericana cl.'N3106'and that of the worst native clone Populus simonii×P.pyramidalis cv.'Chifengensis 34'.There is a linear correlations between the total biomass productions of these six clones with their total leaf area,individualleaf area,mean AGR of leaf area,and daily total net photosynthesis per tree,but a negative correlation with daily total net photosynthesis per unit leaf area.The high biomass production depends on the growth rate of leaf area,height and diameter,and the duration of growth.