Spatiotemporal Dynamics Of Seed Rain And Seedling In Broad-leaved Korean Pine Mixed Forests In Changbai Mountain

Seed dispersal is the self-reproduction and restoration of the principal means in forest ecosystems. Seedlings are the most sensitive period to environmental conditions in the plant life cycle,and has important implications for the population and community succession. In this paper, the different communities (Secondary Populus davidiana-Betula platyphylla forests,Secondary conifer and broadleaved mixed forests and Broad-leaved Korean pine mixed forests)in Changbai Mountain as platform for the study to detect the dispersion of seed rain, and the seedlings were measured in different communities. In the population and community scale, we researched different communities of seed rain, seedling regeneration, explained the differences of community at different succession stages, and predict the feature of plant population.From 2006 to 2009, we collected seventeen species in total, and the Secondary Populus davidiana-Betula platyphylla forests has the most species. Most of the seeds which we collected came from Tilia amurensis, Fraxinus mandshurica, Quercus mongolica, Acer, Maackia and so on. During this four years, the number of the seeds we collected are very large. In 2009 we get the biggest seed rain density, and the smallest in 2008. Secondary conifer and broadleaved mixed forest seed rain density is the largest, followed by the Secondary Populus davidiana-Betula platyphylla forests. Seeds of Fraxinus mandshurica, Tilia amurensis and Acer occupied a large proportion. Spread of seed rain usually has a peak, the peak of seed rain is different in different years, but seed dispersal is always in the same period. Seed rain of different communities is basically the same time. Peaks are mostly concentrated in the same period. Seed rain distribution is very broad, almost throughout the entire plot. We study several important tree species found that the seeds hardly far away from the mother tree, most of the seeds gathered around the mother tree. we collected seventeen species seedlings in total, Secondary Populus davidiana-Betula platyphylla forests the maximum, followed by Secondary conifer broadleaved mixed forest secondary conifer, Broad-leaved Korean pine mixed forests seedlings in the least. Seedling species composition is consistent with the seed, species composition to Fraxinus mandshurica, Tilia amurensis and Acer. The most proportion in the Secondary conifer and broadleaved mixed forests, the seedling of Fraxinus mandshurica accounted for 86% and in the broad-leaved Korean pine mixed forest and Secondary conifer and broadleaved mixed forest the seedling of Tilia amurensis occupied 75% and 41%. we collected lots of seedlings, including Pinus koraiensis, though there is no seeds of Pinus koraiensis. Seedlings of deciduous species were characterized by clumped distribution on the scales less than certain critical points. When the scales was enlarged beyond these points, seedlings were dispersed randomly in different community types.The spatial distribution of Fraxinus mandshurica, Tilia amurensis, Acer, seedlings were positively correlated with their mature trees. it is said that most of seedlings aggregated around the mother trees. The spatial distribution of Pinus koraiensis, Abies nephrolepis's seedlings were negatively correlated with their mature trees. There is no significant relationship between seed density and seedling density, because of second send of seeds and dormancy.