Abstract: Studies were carried out on seed rainfall, duration of seed rainfall, spatial and temporal distribution of seed dispersal of the typical pinus tabulaeformis forest, pinus tabulaeformis forest margin and single pinus tabulaeformis seed tree of Ziwu Mountain forest area in Loess Plateau by laid seed collector (inoculation box). The results indicate that:(1) The total quantity of seed in pinus tabulaeformis forest, forest margin and single tree reached 85.5 seeds·m^-2, 191.5 seeds·m^-2 and 178.0 seeds·m^-2, and the seed rainfall of different seed tree types was significantly different. (2) The seed rain dispersed since the beginning of October, and over at the beginning of November. It lasted about 32 days, seed rain intensity reached peak after ten days. (3) The seed rain intensity in pinus tabulaeformis dense forest was very different from each other, seed distribution was clustered (diffusion coefficient C=33.618). (4) The tendency and proportions of the different seed types were different, the integrity seeds were dominant at the beginning of seed rain, the immature seeds increased rapidly in the latter, and the deformity seeds hardly increased or decreased in the whole process of seed rain,the linear relationship between cumulative fall amount of integrity seeds, immature seeds, deformity seeds and time of rain was evident. (5) Seed rain of forest edge and single tree landed mainly in the range of 1 to 3 m from seed tree. This indicated that the dispersal power of seed rain was gravity mainly.

Key words: spatio-temporal dynamics, seed rain intensity, Pinus tabulaeformis forest, Ziwu Mountain