Abstract: The flux of seed into and out of a unit of habitat determmines the potential population of that habitat. The process is called seed rain. Based on the study of spatial temporal heterogeneity of seed rain in Picea mongolica population, we found that its seed rain is a spatial process, that is to say, the seed rain intensity(SRI)is maximum in the distance 5-10 meters from the mother tree and it is difference in different directions. SRI is maximum with wind, then across wind and finally against wind. Furthermore, the seed rain is a temporal process too. The period of seed rain is about two weeks. SRI is maximum in 2-5 days and its spatial heterogeneity is as former. Based on the seed characters and dispersibility of Picea mongolica, we estimate that a single mature tree(DBH=50cm, Height=17m)can produce 1.6kg seed and 40kg fresh cores.

Key words: macroalgae, attachment, substratum,  , wave exposure.