Honshu Montane Conifer Forest
High altitude forests, such as those in the so-called Japanese Alps, are largely dominated by endemic conifers such as Abies veitchii, A. mariesii (Pinaceae) and Tsuga diversifolia (Cupressaceae), while other endemics conifers like Chamaecyparis obtuse (family), Larex leptolepis (family), Picea koyamai, P. maximowiczii (Pinaceae) and Thuja standishii (Cupressaceae) are locally common.
Hokkaido Montane Conifer Forest
These forests are mainly confined to the montane areas in the south but further north go down to sea level. The three main trees include the endemic Abies sachalinense and Picea jezoensis, the near endemic Picea gledhnii (Pinaceae), but these may be intermixed with Betula ermanii and B. maximowicziana. The shrub layer may include Acer ukurunduense, Euonymus macropteris, Vaccinium smallii and the endemic Ribes sachalinense (Grossulariaceae), while the herb layer species include Cornus canadensis, Tiarella polyphylla, Maianthemum bifolium, Streptopus streptpoides, Trillium tschonoskii, and ferns and fern allies such as Rumohra mutica and Lycopodium serratum var. thunbergii. In certain dry habitats such as on volcanic soil, rocky or gravel ridges and slopes, or in the serpentine areas, as well as in certain wet habitats such as fens, swamps or marshes, Picea gledhnii usually forms the main tree species. In the sparse early stages of P. gledhnii forest on serpentine habitats the associated species characteristically include Berberis amurensis and the endemic Crepis gymnopus (Asteraceae), while the later stages often have dense undergrowth of the near endemic broad-leaved bamboo Sasa kurilensis (Poaceae). On the rock or gravel slopes, the forest floor is usually dominated by Menziesia pentandra, Rhododendron brachycarpum (R. fauriei) or the endemic Carex sachalinensis (Cyperaceae). Wetland P. gledhnii forests are also have varied composition, but species such as Carex middendorfii, Lysichiton camtschatense, Moliniopsis japanica or Osmunda asiatica may dominate the forest floor.
References
Kolbek, J., Srutek, M. & Box, E. O. 2003. Forest Vegetation in Northeast Asia. Kluwer Academic Publishers.
Numata, M. (ed). 1974. The flora and vegetation of Japan. Elsevier Scientific Publishing Company.
Numata, M., Miyawaki, A. & Itow, D. 1972. Natural and semi-natural vegetation in Japan. Blumea, 20: 435-481.
Ohwi, J. 1965. Flora of Japan. Smithsonian Institution. Washington D.C.
Satoo, T. 1983. Temperate broad-leaved evergreen forests of Japan. In: Ecosystems of the World 10 - Temperate Broad-Leaved Evergreen Forests. Elsevier.