Chamaecyparis taiwanensis (Taiwan cypress; ) is a species of cypress, native to the mountains of Taiwan, where it grows at altitudes of 1300âÂÂ2800 m.
It is a slow-growing coniferous tree growing to 40 m tall with a trunk up to 2 m in diameter. The bark is red-brown, vertically fissured and with a stringy texture. The foliage is arranged in flat sprays; adult leaves are scale-like, 0.8âÂÂ1.5 mm long, with acute tips (unlike the blunt tips of the leaves of the closely related Japanese Chamaecyparis obtusa (Hinoki Cypress), green above, green below with a white stomatal band at the base of each scale-leaf; they are arranged in opposite decussate pairs on the shoots. The juvenile leaves, found on young seedlings, are needle-like, 4âÂÂ8 mm long. The cones are globose, smaller than those of C. obtusa, 7âÂÂ9 mm diameter, with 6âÂÂ10 scales arranged in opposite pairs, maturing in autumn about 7âÂÂ8 months after pollination.
It is most commonly treated as a variety of Chamaecyparis obtusa in European and American texts, but more often accepted as a distinct species by Taiwanese botanists. The two taxa differ in ecological requirements, with C. obtusa growing primarily on drier ridgetop sites, while C. taiwanensis occurs on moist soils and with higher rainfall and air humidity.
A related cypress also found on Taiwan, Chamaecyparis formosensis (Formosan Cypress), differs in leaves which are green below as well as above without a conspicuous white stomatal band, and longer, slenderer ovoid cones 6âÂÂ10 mm long with 10âÂÂ16 scales.