Secondary Succession Model of Forest Vegetation and Strategies of Restoration and Rehabilitation of Low Mountains and Hills in Xu-Lian Ecotone

Xu(Xuzhou)-Lian(Lianyungang) Ecotone, located in the north of Jiangsu Province, is militarily a very important region in the eastern China. Its ecological environment has been damaged severely, and the burden of ecological restoration and reconstruction is heavy. Based upon the field survey material of 10 plots(4 650 m~2), the classification system of the forest vegetation on the low mountains and hills in Xu-Lian Ecotone is established, including 2 vegetation type groups, 3 vegetation types, 3 vegetation subtypes, 6 formation groups and 12 formations(i.e., Pinus densiflora forest, Pinus thunbergii forest, Platycladus orientalis forest, Robinia pseudoacacia forest, Pistacia chinensis+Dalbergia hupeana forest, Pteroceltis tatarinowii forest, Celtis bungeana forest, Carpinis turczaninowii forest, Quercus acutissima forest, Quercus variabilis forest, Quercus fabri forest and Quercus variabilis+Machilus thunbergii forest). According to the effects of light intensity on forest edificators , the successional relationships among the 12 formations are analyzed, and the secondary succession model of the forest vegetation of the low mountains and hills in Xu-Lian Ecotone is built. Guided by the model, its strategies of ecological restoration and rehabilitation are discussed.