Abstract: A study was carried out on ecological functions of forest floor,such as standing stock of litters,N and P storage capacity,water holding capacity and detainment of heavy metals,of five typical forest communities in Nanjing.Results show that with regard to standing stock of litters,the water holding capacity and N storage capacity of forest floor,the Quercus acutissima-Q.variabilis community is the highest among the five forest communities,while as far as P and heavy metal storage capacity is concerned the Cinkgo biloba community is the highest and followed by the Quercus acutissima-Q.variabilis community.Comparatively,the Liquidambar formosana and Acer buerqerianum communities are inferior in all these aspects.So in planning and construction of urban forest parks in Nanjing,it is essential to preserve the existing zonal plant communities,Quercus acutissima-Q.variabilis-dominated deciduous broadleaved forest,or build up quasi-zonal plant communities,and maintain integrity of the forest floor of the forestland,which will eventually help improve the urban ecological environment.

Key words: forest community, forest floor, ecological function, Nanjing