Abstract: 63% of the coastline of Guangxi mainland are margined by 498 sets of sea dikes, which destroyed the pristine mangrove forests, with a remain of 5654 hm². About 85% of the remain are dike fringed mangrove forests. The dike discontinued the natural geomorphological profile of mangrove flat.Consequently, Rhizophora stylosa and Bruguira gymnorrhiza are sharply decreased, Lumnitzera racemosa is endangered and Ceriops tagal is disappeared. Excoecaria agallocha and other most landward species can only grow on dike slopes. In contrast, the pioneer species of Avicennia marina and Agiceras corniculatum dominate the present day mangrove forests.The restoration of sea dike fringed mangrove forests are strongly interfered by human's maintenance of sea dikes. The tidal flats edged by sea dikes are not the optimal habitats for mangrove forest development, due to relatively low elevation above mean sea level.It seems that the survival rate of afforestation and the restoration speed of secondary mangrove forests may greatly depend on the sedimentation rate of habitats.

Key words: Sea dike, Mangrove forest, Zonary distribution, Restoration, continuous cropping obstacle, soil enzyme, p-hydroxy benzoic acid, cinnamic acid, peanut, yield., soil available nutrients