<正>为了探测含零较多的计数数据对ZIP回归模型的影响，基于EM算法和完全数据似然函数，笔者利用数据删除方法研究了模型的全局影响，得到了参数估计的一步近似表达式以及相应的广义Cook距离和Q-距离，并研究了在EM框架下的广义杠杆值。最后，通过实际问题说明了所得统计量的有效性。

The community structure of urban forest, the basis of urban forest research, are determined by different plants species and its different patterns of spatial distributions. The paper provides an overview of the past and current research on community structure both at home and abroad from three aspects: the diversity research, dynamics research, the species selection and the models of plantation arrangement. It also advances development tendency of community structure in the future as well.