Beech (Fagus crenata) forests and Oak (Quercus spp.) forests are typical forest vegetation of the moderate sites of the cool temperate zone in Japan. Quercus forests consists of Quercus serrata forest of warm temperate zone and Quercus crispula forest of cool temperate zone, and this study covers the latter. Generally, Fagus crenata forest occurs in a site with stable soil conditions such as slopes or the level grounds, on the other hand, Quercus crispula forest occurs on the severe conditions compared with beech forests such as the steep ridge, the rocky site and the sandy soil. Both forests are integrated into the phytosociological class; Fagetea crenatae Miyawaki, Ohba et Murase 1964, Fagus crenata forests are divided order; Saso-Fagetalia crenatae Suz.-Tok. 1966 and Quercus crispula forests are divided into order; Tsgetalia sieboldii Suz.-Tok. 1966 and Carpino cordatae-Quercetalia grosseserratae Hoshino 1998. However, phytosociological studies of both forests have been conducted separately, therefore there are many unclear points their floristic compositional relationship. Until now, their direct comparisons have not been done except regional research, and the synthesis table shown in this lecture is the first attempt on a nationwide scale.