Before the 921 earthquake, the forest vegetation zones were mainly classified into Ficus-Machilus forests, Machilus-Castanopsis forests, and forests dominated by some pioneer species in this reserve. The steeper slopes and dry environment reduced human disturbances, and precious species such as Zelkova serrata, Schima superba, Liquidambar formosana, Ulmus parvifolia, Firmiana simplex, Cyclobalanopsis glauca, and Carpinus kawakamii grow on the lower slopes (Liao 1992). The 921 earthquake changed the LU/LC completely. The area affected by landslides was covered by pioneer species such as Trema orientalis, Sapium discolor, Mallotus paniculatus, Mallotus japonicus, Rhus chinensis, Fagara ailanthoides, and Macaranga tanarius. A. formosana grows well in this area.
Arundo formosana can be classified into the category “grass” and the family Poaceae (subfamily Gramineae). It can hang downward and thrive in crevices and cliffs and often grows and forms a secondary grassland. The seeds of A. formosana are small, light, and can float in the wind. The species can be found at low altitudes in Taiwan, Orchid Island, and Green Island. The leaves are alternate, long-lanceolate, and papyraceous, with basal filamentous hairs. Leaf length is 10-20 cm and width is 1-2 cm. Flowering occurs from June to November as a panicle, terminal, light yellow spikelet, with three flowers about 0.6 cm in size. A. formosana is a high-pulp material, and the roots and stems are used in the manufacture of handicrafts and baskets in Taiwan (Endemic Species Research Institute 2003). Almost all the steep slopes of Jiou-Jiou Peaks Natural Reserve were covered by this species (Fig. 18.2).
