Abstract: From the view of disturbance ecology,this paper studied the species group age structure of Larix gmelini population in the north Daxinganling Mountains and its relation to natural disturbance factors, such as forest fire, windfall etc. Following results were obtained: The species group age structure of Larix gmelini population consists of one or more discrete age waves and can be derided into three groups: One-generation, two-generation and multi-generation, moreover eleven types according to the structure state. Natural disturbances have an important effect on the age structure. Forest fire almost affacts all age waves, and windfall and windbreakage are also proved to be important to the late generations. Generally, the weak fire with high frequency favors to form two or multi-generation, the strong fire with low frequency favors one-generation. The major reason for the coexistence of many types of age structure is ascribed to the differences in natural disturbance regime in each region. Age waves, being basic unit of age structure, evidently show β distribution feature with the shapes of right deviation, left deviation, progressive decrease and increase distribution. The shape of age waves is related to the environment of species group, which reflects the regeneration processes comprehansively.

Key words: Larix gmelini popuplation, Species group age structure, Age wave, Natural disturbance, Forest fire