Abstract: On the basis of field plot survey data,characteristics of planted Robinia pseudoacacia forest dieback were statistically analyzed.The results showed that total dieback or dead ratio of planted Robinia pseudoacacia forest was 41.4%.According to tree height and breast diameter data,239 Robinia pseudoacacia trees were classified into three classes, which indicated the dieback ratio increased from 18.2% to 36.3% with tree age.The dieback degree matched normal distribution with parameters of (4.04,2.27),and moderate and severe dieback and dead Robinia pseudoacacia was 66.7 percent of all dieback and dead Robinia pseudoacacia,which indicated that the planted Robinia pseudoacacia forest in the Yellow River Delta was in the status of severe dieback,and needed monitoring of the dieback status and the mechanism needed to be studied and managed synthetically.

Key words: planted Robinia Pseudoacacia forest, dieback, statistic, Yellow River Delta