Broad-leaved and mixed cooltemperate forests from the class Fagetea crenatae Miyawaki, Ohba et Murase 1964 on Kunashir Island (the Kurils archipelago)

Abstract

This study presents the classification and description of three new associations of cool-temperate zonal forests of the vegetation class Fagetea crenatae Miyawaki, Ohba et Murase 1964 on Kunashir and Hokkaido islands. The Filipendulo camtschaticae–Aceretum mayrii ass. nov. encompasses broad-leaved forests in eutrophic moist ecotopes dominated by Acer mono subsp. mayrii. The Abieti sachalinensis–Quercetum crispulae ass. nov. represents zonal mixed forests dominated by Quercus mongolica var. crispula with an admixture of coniferous tree species Abies sachalinensis, Taxus cuspidata, and Picea jezoensis (the latter only on Kunashir Island, in forests of the subass. piceetosum jezoensis). The Hydrangeo paniculatae–Quercetum crispulae ass. nov. includes secondary species-poor forests dominated by Q. mongolica var. crispula, Betula ermanii, or B. pendula subsp. mandshurica. All associations feature a dense understory of dwarf bamboo species Sasa spp., with the densest tickets found in Hydrangeo paniculatae–Quercetum crispulae forests. We also validated the union Carpino cordatae–Quercion crispulae Takeda, Uemura et Nakanishi ex Korznikov, Dzizyurova et Petrenko all. nov. which represents the zonal cool-temperate broad-leaved and mixed forests in Hokkaido, Sakhalin, Iturup and Kunashir. Broad-leaved forests of Kunashir exhibit lower species diversity compared to Hokkaido, missing typical temperate tree species such as Acer palmatum, Carpinus cordata, and Tilia japonica.