Abstract: The spatial pattern and correlation of Caragana roborovskyi at different age levels on different slope aspects in Gaolan County,central Gansu Province was analyzed by using the Ripley K function in the point pattern analysis.The results showed that the C.roborovskyi population in class I and II was dominant in the whole population,and the population regeneration was good.The C.roborovskyi population in class I was clustered in the whole study scale,and that in class II,III and IV was distributed randomly on north slope.On the northwest slope,the population in class I was distributed in an obvious aggregation,that in class II was mostly in a small-scale aggregation and in a random large-scale aggregation,and that in class III and IV was randomly in any-scale aggregations.On the southwest slope,all the age classes of C.roborovskyi were distributed randomly on all scales.On different slopes,the population in class I and II was negatively correlated on the small scale,and it was unrelated with the increase of scale.The population in class III and IV was not related on any scales.In addition,the population at all other age levels was negatively correlated.The population regeneration of C.roborovskyi was not only affected by interspecific and intraspecific competition,but also related to the habitat conditions at different slope aspects.When C.roborovskyi was used to restore and rebuild the soil erosion area in central Gansu Province,the 4 m line spacing between shrubs was suitable on southwest and south slopes,and 3 m one was suitable on northwest and the north slopes.

Key words: slope aspect, Caragana roborovskyi, population, spatial pattern, correlation, central Gansu Province