Chamaecyparis obtusa (Japanese cypress, hinoki cypress^[2] or hinoki; Japanese: 檜 or 桧, hinoki) is a species of cypress native to central Japan in East Asia,^[3][4] and widely cultivated in the temperate northern hemisphere for its high-quality timber and ornamental qualities, with many cultivars commercially available.

Quick Facts Chamaecyparis obtusa, Conservation status ...

Chamaecyparis obtusa
A 700-year-old hinoki tree at Daichi-ji temple in Gifu Prefecture, Japan
Conservation status
Near Threatened  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Gymnospermae
Division:	Pinophyta
Class:	Pinopsida
Order:	Cupressales
Family:	Cupressaceae
Genus:	Chamaecyparis
Species:	C. obtusa
Binomial name
Chamaecyparis obtusa (Siebold & Zucc.) Endl.
Subspecies
Chamaecyparis obtusa var. formosana

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It is a slow-growing tree which may reach 35 m (115 ft) tall^[5] with a trunk up to 1 m (3 ft 3 in) in diameter.^{[citation needed]} The bark is dark red-brown. The leaves are scale-like, 2–4 mm (0.079–0.157 in) long, blunt tipped (obtuse), green above, and green below with a white stomatal band at the base of each scale-leaf. The cones are globose, 8–12 mm (0.31–0.47 in) in diameter, with 8–12 scales arranged in opposite pairs.

The plant is widespread in Japan. The related Chamaecyparis pisifera (sawara cypress) can be readily distinguished in its having pointed tips to the leaves and smaller cones.^[3][4] A similar cypress found on Taiwan is treated by different botanists as either a variety of this species (as Chamaecyparis obtusa var. formosana) or as a separate species Chamaecyparis taiwanensis; it differs in having smaller cones (6–9 mm diameter) with smaller scales, and leaves with a more acute apex.^[3][4]

It is grown for its very high-quality timber in Japan, where it is used as a material for building palaces, temples, shrines, traditional noh theatres, baths, table tennis blades and masu. The wood is lemon-scented, light pinkish-brown, with a rich, straight grain, and is highly rot-resistant. For example, Horyuji Temple and Osaka Castle are built from hinoki wood. The hinoki grown in Kiso, used for building Ise Shrine, are called 御神木 go-shin-boku, or "divine trees".

It is also a popular ornamental tree in parks and gardens, both in Japan and elsewhere in temperate climates, including western Europe and parts of North America. A large number of cultivars have been selected for garden planting, including dwarf forms, forms with yellow leaves, and forms with congested foliage. It is also often grown as bonsai.^{[citation needed]}

The lignans chamaecypanones A and B, obtulignolide, and isootobanone can be found in the heartwood of Chamaecyparis obtusa var. formosana.^[18] The biflavones sciadopitysin, ginkgetin, isoginkgetin, podocarpusflavone B, 7,7''-O-dimethylamentoflavone, bilobetin, podocarpusflavone A, 7-O-methylamentoflavone, amentoflavone, hinokinin and hinokiflavone have been confirmed in the leaves of the plant.^[19] Chamaecydin was first discovered in the seeds of C. obtusa.^[20] The essential oil of Chamaecyparis obtusa contains a wide range of chemical compounds, including but not limited to the following: sabinene, elemol, myrcene, limonene, terpinen-4-ol, eudesmols, α-terpinyl acetate, α-terpinolene, α-terpineol, 3-carene, α-pinene, γ-terpinene, camphene, bornyl acetate, 1-methyladamantane, cuminol, eucarvone, 2-cyclopenten-1-one, 3,4-dimethyl-, 1,3-dimethyl-1-cyclohexene, calamenene, τ-muurolol, borneol, α-cadinol, β-thujaplicin.^[21][22] Some of these compounds are fragrances or intermediates used in the fragrance industry. Thus, the C. obtusa essential oil is used in perfumery and personal care products, such as soaps, shampoos, cosmetics.^[22] Hinoki wood is used as a traditional Japanese stick incense for its light, earthy aroma.^[23]

Essential oil distilled from its wood is uniquely scented and highly valued.^[24]

Hinoki pollen can cause pollinosis, a specific type of allergic rhinitis. Chamaecyparis obtusa, along with Cryptomeria japonica (sugi, Japanese cedar), is the leading source of allergic pollen in Japan and a major cause of hay fever in Japan.^[25]

• C. obtusa 'Nana Gracilis'
• Cypress bark is used as a traditional roofing material (hiwadabuki) at Tō-ji in Kyoto
• Illustration
• Bonsai
• Tanzawa Mountains, Japan
• Foliage; underside showing white stomatal lines