The purpose of this paper is to unveil the influence of forestation on revegetation. Investigations of vegetation have been conducted on the forest of Man-made filled slopes along Nagasaki expressway. The investigation places along expressway were divided into evergreen broad-leaved forest and mixture forest. As for the layered structure of ligneous species in the forest along expressway, after ten years, it became forest mainly composed of the third layer. And after 25-30 years, it became forest mainly composed of the second layer. As for the places that planted at the construction of expressway, the cover rate of natural ligneous species was low at higher layer. The result suggested that the planted trees took dominant rate in the revegetation. In comparison with outside forests of the expressway, there was the characteristic that the number of plant species per 1,000m2was fewer than the forest edge type, and was similar to forest interior type. It indicated that the forestation controlled increase in the plant species. Additionally, the result showed that the relative illumination and the cover rate of undergrowth vegetation varied according to the type of forestation. The estimation showed higher correlation with approximately 82%. It was approximately 66% with climbing plants.
