Abstract: The biological and physiological characteristics, community structure and dynamic , biomaas and productivity, nutrient cycling of Acacia mangium were studied over 10 years at Heshan Station, Guangdong, China. The results showed that Acacia mangium was a quickly and widely adaptive species, and could be planted in tropical and lower-subtropical zone. Because of high photosynthesis rate and rational vertical structure, the productivity of Acacia mangium forest was high. The biomaas of the forest increased annually, but the annual growth of biomass and nodule biomass decreascd annually from the fourth year. This indicatad that N limited the growth of biomass. The nodule biomass and the amount of litterfall and nitrogen fixation of Acacia mangium forest were high. Quick cycling of the nutrient demts (especially N) in the forests proteced the soil and increaved the frtility in the soil.

Key words: hedgerow, soil aggregates, destruction rate of soil structure, slope, soil and water loss.