Hinoki, Chamaecyparis obtusa

A common companion of the Japanese cedar, Cryptomeria japonica, is the famous Japanese hinoki, Chamaecyparis obtusa.  Hinoki is a smaller tree, however in ancient times massive ones existed – alas those forests of old are long gone.  Nevertheless, this tree has a special place in Japanese culture, revered mostly for its wood, but also for the fragrant essential oils found throughout its tissues.

Chamaecyparis obtusa a massive evergreen coniferous tree reaching 35 meters in height, and with a trunk up to a meter in diameter.  The bark is reddish brown to silvery and grows in long strips.  In young trees these can flake off in thin strips, but older trees have more compact bark generally, and thicker in substance.

The branches grow in  a whorl up the trunk and tend to hang down a bit.  Young trees are cylindrical, having broad and rounded crowns with old trees having more irregular branching and more pendulous branches.  Older specimens can have branch-less trunks for the first several meters, especially in low light conditions such as plantation forests.

The leaves are dark green to blue-green, scale-like in appearance and blunt at their tips.  They grow on branchlets that are spreading, fan-like, and tend to be in a relatively flat plane.  These branchlets break off intact when they fall rather than falling apart on the tree. The pollen cones and seed cones are born separately, but on the same tree (monoecious habit).  The red-brown pollen cones grow singly on the outermost twigs and are roughly conical shaped and are only 3-5 mm long each.  The seed cones start out growing bright green and eventually turn a rich brown.  They are nearly perfectly round and are about 2 cm across.

This common conifer is found in southern Japan from western Honshu, Shikoku, and Kyushu.  The variety formosana is reported from Taiwan and sometimes is considered a separate species, C. taiwanensis.  Both varieties are very rare in the wild with just a few remnant populations. While hinoki prefers moist woodlands, it also can be found on exposed ridge-lines, from 0-1000+ meters elevation.  Trees can be in mixed stands with other conifers or most often with broad leaf trees, both deciduous and evergreen.

This is another of Japan’s more significant trees.  Hinoki wood has been cherished throughout the centuries as a building material for traditional structures such as shrines and temples since it is resistant to rot. It also is used in Shinto ceremonies and to build special baths particularly at hot springs (known as onsen).  The wood is fragrant, clean, and beautiful to look at.

A freshly constructed building made of hinoki wood is a pleasure to step inside due to the cocktail of organic compounds found in its essential oils – the word that comes to mind is “clean”, and perhaps it is this quality that makes it important in purification rituals in Shinto religion.  The wood is so resistant that well built structures can last 1000 years, and the remnant artifacts made of hinoki date back even further, into the Yayoi Period, (BC1000-AD200).  It is still used in building today, but only for high end market products carrying equally high end prices.

Hinoki essential oil is jammed full of aromatic chemicals.  One of the more celebrated components is hinokitol, a monoterpenoid found in many members of the cypress family, the Cupressaceae.  This compound is low in toxicity and has been proven to inhibit the growth of some bacteria, including Chlamydia trachomatis.  On the popular market hinoki essential oil is sold as another natural cure all and can be found in products such as perfumes, toothpaste, and hair tonic.  It also is used in aromatherapy.  While such uses are questionable from a pragmatic perspective, they will do little harm to the user, except maybe empty their wallets – these products, in particular the oil, are often sold at high prices.

Hinoki’s usefulness has lead to the demise of this species in the wild.  It is extremely rare throughout its range (including Taiwan), showing up on red lists of endangered species.  The irony of it is that the tree is very common today in Japan and can be seen on almost any hill or mountain in the southern regions.  My neighborhood is actually surrounded in hinoki forest.  Volunteer seedlings are always coming up in my garden.  The odd reality is this:  while hinoki plantation forests are common today, native forests are nearly gone, existing only in remnant stands.  Big specimens are uncommon as well, being seen occasionally at shrines and temples, but far less than the more celebrated sugi.  In fact, I can’t honestly say I’ve seen a true wild specimen ever.  The largest specimen I know of is in the middle of a hinoki plantation along an old concrete road near my house.

Hinoki plantation forests, like their sugi counterparts, are biologically simplified systems, providing poor habitat for most plants and animals.  Still, many fern species are perfectly happy in them and among the orchids, both Liparis nervosa v. bituberculata and Cephalanthera falcata seem to actually benefit from these forests.

Seedling hinoki can be seen where ever adult trees are present, sometimes carpeting the ground or an old tree stump.  This is definitely a tree with a future in Japan, but the forests of old are by and large a thing of the past.

The name, hinoki, simply means “cypress”.   It it tempting to call it the “fire tree” because hi means fire and ki tree, but this name predates current syllabaries so such an interpretation is likely false.  It is true that hinoki wood is burned in Shinto rituals, but apparently this has nothing to do with its name.  Since ancient Japanese was born in preliterate times, names dating to that period remain obscure in many cases.

Hinoki is widely grown throughout warm temperate to cool temperate climates the world over.  Like sugi, many cultivars have been isolated, some being very dwarf forms less than a meter tall and others becoming small trees.  Forms such as ‘Crippsii’, ‘Nana Aurea’,  and ‘Nana Gracilis’ are common throughout the world, often in private gardens, as hedges, and in public and commercial plantings.  Oddly, here in Japan, it is much less commonly used in the landscape than in America.

It seems to do well in a wide range of soil types, but is no doubt sensitive to truly basic soils.  It is more drought tolerant than its common companion, Cryptomeria japonica, but still needs steady water throughout the year.  It probably will not thrive in climates that are low in humidity or experience cool conditions year round.  These trees like warm to hot summers with ample moisture, and require a true cool down in winter.

This tree should be able to grow in USDA zones 8-5, and though some sources list their cold hardiness to zone 4, they may prove unreliable without protection from cold dry winter winds.  They do seem quite a bit more cold resistant than Cryptomeria.  The Taiwanese variety is probably much less cold hardy, perhaps only to zone 8 or 9.  Most sources insist this tree requires full sun conditions at least part of the day, or they will go into decline.  From my observations, young trees in plantation forests can withstand moderate shade as long as they are able to grow upwards into the canopy.

There is little to say of this tree that isn’t positive.  It has lovely wood that smells good, it is a beautiful tree to look at, either as a full grown wild type or one of its many cultivars, and it isn’t weedy.  Loved throughout the world as a garden subject, and also in its native homeland for the qualities of its wood, bark, and needles, hinoki has made its impact on human culture.