Species Composition of the Alnus faurei Community in the Heavy-Snow Region of Central Japan

Alnus faurei shrubs grow on mountain slopes and along valleys on the Japan Sea side of Japan where forest vegetation is frequently broken by snow effects such as avalanches, snow creep, and snow pressure. All Alnus faurei stands in the whole region in which Alnus faurei occurred were identified as belonging to the Elatostemo-Alnetum faurei association in this study This association was characterized and differentiated by Alnus faurei, Plectranthus trichocarpus, Cirsium nipponicum, Elatostema umbellatum var. majus, Equisetum arvense, and Impatiens textori through comparison with the Arunco-Alnetum pndulae association, which occurred in similar habitats. The Elatostemo-Alnetum faurei was, moreover, divided into 5 subassociations. This association included some species of the Fiilipendulo-Artemisietea montanae class in high frequency, because the association occurred on habitats adjacent to tall-herb communities The Arunco-Alnetum pendulae included more species of the Fagetae crenatae class than the former association. It was expected that these differences in species composition reflected the fact that the Arunco-Alnetum pendulae occurred on habitats adjacent to forest communities. These associations were identified as belonging to the Wiegelion hortensis alliance and the Weigelo-Alnetalia firmae order by Alnus spp.. Weigela hortensis, etc