Kerrio japonicae-Quercetum serratae : A new association in the riparian forest community on the gravel-river bed

Abstract

A new association of deciduous broad-leaved riparian forests, namely, Kerrio japonicae-Quercetum serratae is described on the Pacific Ocean side in central Honshu, Japan. This association is dominated by Quercus serrata and is accompanied with Zelkova serrata, Castanea crenata, Prunus spp., Acer spp., and Carpinus spp. in the tree layer. Comparing with the other associations of Quercus serrata, Kerrio japonicae-Quercetum serratae is characterized by the elements of Fraxino-Ulmetalia Suz.-Tok. 1967, such as Kerria japonica, Rhamnus japonica var. decipiens, Ostrya japonica, Acer mono var. ambiguum, and Lilium cordatum. The distribution of this association is inland area of central Honshu of the intermediate temperate zone between warm temperate zone and cool temperate zone. The habitats of this association are riverside stable terraces in the middle reaches with surface deposits consisting of cobbles, gravels, and coarse sands. This association can be classified into the following upper unit: Carpino-Quercion serratae Miyawaki et al. 1971, Quercetalia serrato-grosseserratae Miyawaki et al. 1971, Querco serrato-Pinetea densiflorae Nakanishi, Takeda et Hattori 1977. The Kerrio japonicae-Quercetum serratae can be regarded as one of the edaphic climax of alluvial plain.