The distinctive deep dark-green forest forms Kurotanichi ("Black Wetland"), where Japanese white pines gather.
At the foothills where Mount Chausu and Hachimantai intersect, the earth is black with peat. When the deep winter snow melts in spring, the vast black valley peatlands bloom with aquatic plants like fringed galax and other wetland flora thriving among last year's dead grass. In summer, geranium, deer cabbage, and small daikon-sou flowers sway in the wind. In autumn, clusters of gentian dye the landscape a vivid purple.
From the Kurotanichi Observatory, located 700 meters from the wetland entrance, you can enjoy a panoramic view of the Kurotanichi Wetland and its pond. Along the boardwalk trail lies Kuma no Izumi (Bear's Spring).
Along windy ridgelines, plants adapted to dry conditions thrive. In sheltered spots beneath cliffs where snow lingers and winds don't reach, plants adapted to damp conditions can be found. However, this environment slows plant growth, so wildflowers like Hamayu, Aleutian Azalea, Carthamus, Ugo Thistle, and St. John's Wort only bloom after the spring alpine flowers in the summit region begin to fade.