On the Betula chichibuensis community developing in the limestone of Kataiwa area in Tono City, Iwate Prefecture, Northeastern Japan

Floristic composition

Stratification

Regeneration

Edaphic climax

As part of the research on the peculiarity of the vegetation which has developed in the limestone area, phytosociological investigation was conducted in the Betula chichibuensis community in the limestone of Kataiwa area in Tono City, Iwate Prefecture. The distribution of B. chichibuensis is limited to the limestone area around the Chichibu Mountains of the Kanto district and the Kitakami Mountains in Iwate Prefecture. Therefore, B. chichibuensis community of this investigation area was compared with that of Mt. Tenso in the Chichibu Mountains in floristic composition. According to the investigation, there were few species common to both area and each community consisted of the original species. In the community of this investigation area, B. chichibuensis was dominating overwhelmingly in the Arborescent Primary layer. And Acer japonicum・Fraxinus sieboldiana・Tilia japonica・Viburnum dilatatum・Sasamorpha borealis was dominating in the Fruticose layer, and Carex sachalinensis・Syneilesis palmata・Carex nanella etc. was dominating in the Herbaceous layer. Moreover, B. chichibuensis was occurring in all layers from the 2nd Fruticose layer to the Arborescent Primary layer. Many individuals of B. chichibuensis which constitutes the Arborescent Primary layer in them were of a diameter of 15cm or more and less than 20cm at breast height. The individual with the thickest stem had even grown to a diameter at breast height of 39cm. B. chichibuensis had grown well under restrictive site factor, such as at cliff edges where other species cannot grow easily. And if there is nothing at such site factor, we may conclude that B. chichibuensis community cannot be continued as edaphic climax.