Population life table and time sequence prediction of Alnus sibirica

Based on the population life table and survival analysis theory, the population static life table of Alnus sibirica was compiled by spatial sequence instead of time method and homogenization technique, which replace the age structure with tree diameter structure. And the population loss rate curve, survival curve, death curve, survival function curve and time series forecasting chart were drawn to analyze the population dynamics. The results illustrated that the survival curve of Alnus sibirica was likely to the type of Deevey-Ⅱ. The survival curve, mortality rate and extinction rate curve and four survival functions of Alnus sibirica population showed that the characteristics of this population were stable in early age period, fluctuant in middle age period, then recessionary in old age period. The time series analysis showed that the population quantity tended to decrease with the age increased in same time curve, meanwhile, the number of juvenile population decreased gradually and the proportion of individuals in middle and old age period increased gradually over time. The population has a poor natural regeneration ability, and the population will tend to decline under natural conditions.