Secondary forests are important component of landscape in agricultural area. They had been maintained as a source of fuel, manure and material for various uses until the late 1960s in Japan. However, recently most of them have been abandoned or underused management, due to lose economic value under the change of modern trends. Communities and populations of secondary forest may be modified by their human activities. As a result, species composition and richness in secondary forest have changed.

In this study, we observed changes in the species richness and composition in secondary forests after more than 20 years. Study site located Inashiki upland that urbanization had progressed rapidly over the last two decade, kanto plain, Japan. We investigated 110 plots by vegetation survey(Braun-Blanquet,1964) in secondary forest(pine forest, deciduous broad-leaved forest, evergreen broad-leaved forest, coniferous forest, bamboo forest) in 1988.7~9. And we revisited and reinvestigate same plots(N=82plots,28plots diseased by land formation) in 2011.8~9. All stand of pine forest(dominated by Pinus densiflora) in 1990 were changed to deciduous or evergreen broad-leaved forest(dominated by Quercus serrata and Quercus myrsinifolia) in 2011. We estimated changes in species composition and diversity with respect to the Successional stage.