The Population Life Table and Periodic Fluctuation of the Relict Plant Glyptostrobus pensilis

In order to determine the population state of Glyptostrobus pensilis,analyze its past population structure and pre-disturbance situation and forecast its future population dynamics,the population life table and periodic flutuation of G.pensilis were analyzed by space deducing time method.The static life table,the survivorship curve,the mortality rate curve and danger rate were compiled using the diameter at breast height class to represent the age class structure and smooth out technique.The results showed that the survival curve of the population appeared to be of the Deever-Ⅲ type.The high mortablity of seedlings was one of the main reasons which led the G.pensilis population becoming endangered.The natural rege-neration process of the G.pensilis population can be represented by the flutuation of the distribution of the number of trees in different age grades.Spectral analysis of the population showed that the natural rege-neration of G.pensilis was a minor periodic change in the tenth age grades.