Abstract:Fagus hayatae, a rare and endangered plant in China(category II), is distributed in China. Understanding the age structure and number of F.hayatae population is useful to reveal population dynamics and life-history traits. We investigated F.hayatae population distributes on the north slope of Laolin Valley in Micangshan Nature Reserve, and obtained a static life table on the basis of age class structure by using the smoothing out technique. Then, we analyzed the population quantitative dynamics of F.hayatae according to the results of survival and spectral analysis. The population was composed of 52% young individuals(including seedlings), 45.5% of mature individuals, and 2.5% of old individuals. Two peaks of higher mortality rate were in 1st and 17th age class periods of the lifespan. In addition to two big drops, the population survival rate decreased gradually from 1st to 24th age class. However, the opposite trend was found in cumulative mortality rate curve. By spectral analysis, the regeneration process of the population showed the marked periodic variations. The amplitude Ak had the largest values at fundamental wave A1 and harmonic wave A2 reflecting the lifespan of F.hayatae individuals. The quantitative fluctuation of population exhibited obvious small cycles, such as A3 and A7, which closely related with height growth and intense competitions during radial growth phase, respectively. Our results showed that the survival curve of F.hayatae population in Micangshan Nature Reserve was agree with Deevey type Ⅲ, and the population dynamics exhibited a trend that population size decreased sharply at young stage, kept stably at mature stage, and declined at old stage.