Scientific name: Chamaecyparis obtusa (Siebold et Zuccarini) Endlicher 1847

Synonyms: Chamaecyparis acuta Beissn., Chamaecyparis andelyensis Gordon, Chamaecyparis breviramea Maxim., Chamaecyparis keteleri Standish ex Parl., Chamaecyparis lycopodioides (Gordon) Sénécl., Chamaecyparis pendula Maxim., Chamaecyparis tsatsumi (Slavin) Slavin, Chamaepeuce obtusa (Siebold & Zucc.) Zucc. ex Gordon, Cupressus acuta Lavallée, Cupressus breviramea (Maxim.) F.Muell., Cupressus obtusa (Siebold & Zucc.) F.Muell., Cupressus pendens F.Muell., Juniperus sanderi Mast., Retinispora filicoides (Hartw. & Rümpler) Veitch ex Gordon, Retinispora fusinoki Zucc. ex Gordon, Retinispora lycopodioides Gordon, Retinispora monstrosa Carrière, Retinispora obtusa Siebold & Zucc., Retinispora sanderi (Mast.) Sander, Retinispora tetragona R.Sm., Shishindenia ericoides (Boehm. ex Beissn.) Makino ex Koidz., Thuja obtusa (Siebold & Zucc.) Mast.

Common names: Hinoki cypress, Japanese cypress, Hinoki (Japanese)

Description

Tree to 30(-52) m tall, with trunk to 1.5(-3) m in diameter. Bark reddish brown, rather smooth, peeling in wide, thin strips. Crown broadly conical. Branchlet sprays drooping, often fan-shaped, with waxy white Y’s beneath outlining the leaf contacts. Scale leaves 1-2.5 mm long, dark green, with a round gland. Leaf tips blunt (hence the scientific name), those of the facial leaves not touching the base of next pair. Pollen cones about 4 mm long, with three to five pairs of pollen scales, each scale with three or four yellow pollen sacs. Seed cones spherical, 9-12 mm in diameter, with four or five pairs of seed scales. Seeds two to four (to six) per scale, 2-4 mm long, the wings no wider than the body.

Japan and Taiwan; (10-)1,000-2,500(-2,800) m.

Conservation Status

Red List Category & Criteria: Near Threatened

Chamaecyparis obtusa's individual varieties have been assessed as Near Threatened in Japan (var. obtusa) and Vulnerable in Taiwan (var. formosana). The Japanese variety is the more widespread and numerous so the species as a whole is also assessed as Near Threatened, on the basis of a population decline which may approach 30%. The two varieties of this species occur in different (micro)habitats: Chamaecyparis obtusa var. obtusa is generally occupying more xeric sites on ridges or slopes; Chamaecyparis obtusa var. formosana can form extensive forests in atmospherically damp and often edaphically wet sites. Both occur in mixed conifer/angioserm forests, in which the conifers are mostly emergents and the angiosperms form lower layers of canopy. This species is considered as nationally 'not threatened' in Japan but there is disagreement about the assessment of likely rates of decline in the past due to heavy exploitation. In Taiwan, the var. formosana is assessed as Vulnerable. The wood of Chamaecyparis obtusa has been used for centuries in construction of temples and other traditional buildings because of its fine quality and high durability in outdoor conditions. The Japanese have largely turned to sources outside Japan to obtain timber of related species, especially those occurring on the Pacific coast of North America. This species is among the most widely used in horticulture and numerous cultivars, obtained in Japan, Europe, the United States and New Zealand, are in the trade. The species is particularly suitable for the clonal propagation of dwarf forms ('tennis ball conifers') with compact growth selected from cuttings from witches brooms; these grow often very slowly and are therefore considered ideal for pot-grown patio plants, rockeries, etc. The number of cultivar names under this species is rapidly outgrowing the capacity to list them and even the most comprehensive register of cultivated conifers, so far compiled and published by the Royal Horticultural Society in England for the names from letters A-J (Leslie 1992), cannot claim to be nearly complete. Protected subpopulations occur in Yuanyang Lake Reserve and Yushan National Park. Plantations have also been established. A ban on logging is now in effect in both Taiwan and Japan.

References

Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland