Abstract: The genetic diversity of 13 natural populations of Sorbus amabilis Cheng ex Ya from diferent distribution regions was investigated using RAP D ．Fourteen primers were screened from 40 ten-bp arbitrary primers，and a total
of 105 DNA fragments were amplified，among which，30(28．6％)were polymorphic．DNA molecular d~drograms were established for the 13 natural populations，based on UPGMA and Neighbo r-Joining．The result
showed that S．amabilis had a low genetic diversity，and its adaptability tO environmental change WaS weak．The genetic diversity of S．amabilis among the 13 natural po pulations were prim arily related tO their geographic distribution．
Its special evolutionary himory，man-made destruction，natural disaster(fire，plant diseases and insect pests etc．)and genetic drift caused by small population were the main reasons for the low—level genetic diversity
of S．amabilis and its endangered position．

Key words: degraded red soil, light fraction organic carbon, particulate organic carbon, process of vegetation restoration, rate constant for C transfer (k), Pinus massoniana plantation.