THE SUMMARY REPORT FOR STUDIES ON THE TROPICAL FOREST ECOSYSTEM IN JlANFENLING REGION, HAINAN ISLAND V.ECOLOGICAL CONSEQUENCE OF SHIFTING AGRICULTURE;Ⅵ.REGENERATION AND SUCCESSION;Ⅶ.CONCLUSION

The following changes have been observed on the land for shifting cultivation in tropical forests:increase of air and soil temperature;decrease of relative humidity;ever worsening erosion due to the increase of surface runoff;decrease of water infiltration, water-holding capacity of soil and soil fertility.Continual cultivation transformed the forest land into xerophytic herb community at last, which was hardly to be reforested.The regeneration and succession process of tropical forest had a lot to do with human activities.Taking the selective cutting with a maintenance of above 0.4 canopy density is beneficial to the restoration of the forest.Protection of the tropical forest ecosystem should be considered as the main managerial principle of Jianfengling forest region, Hainan Island.