Study on Change of Soil in Several Plantations in Tropical Area of Yunnan

Soil fertility of the plantations of Paramichelia baillonii, Betula alnoides, Acacia Mangium and Altingia excelsa in tropical area of Yunnan does not decline rapidly, and the physical and chemical properties of forestland are not affected greatly if the plantations can be managed properly. The approximate trend of the change of soil in the plantations of four species is that soil fertility declined slightly from 1993 to 1995, and rose a little from 1995 to 1997.