Dr Stephen J Bowe, Senior Lecturer at Liverpool John Moore’s University and author of Mulberry, published in 2015, explains why mulberry wood from the Japanese Izu Islands has become the world’s most expensive wood.

We usually think of mulberries either in terms of their fruit (black mulberry) or their leaves (white mulberry), used to feed silk worms -- or indeed their ornamental beauty as trees. But for centuries mulberry wood has been highly prized by makers of cabinets, bowls and functional and decorative objects. And the most sought-after of all is Shimakuwa, or island wood, from mulberry trees that grow only on the Izu Islands of Japan.

And just as the British Royal family has marked its association with mulberry trees by hosting the national collection, so the wood from the Izu island mulberry trees, sometimes over 1000 years old, has traditionally been gifted to the Japanese Royal family.

The Izu Islands are in a chain of volcanic islands that run for thousands of miles off the coast of Tokyo and are considered part of the Tokyo prefecture. The two main islands associated with mulberry trees are Miyakejima and Mikurajima.

Now a nature reserve, with highly restricted access, these photogenic islands have become fashionable “extreme” holiday destinations. Frequent seismic activity and very high levels of sulphurous gases are a significant hazard for visitors, who sometimes have to wear gas masks. 

But this hostile environment has bestowed unique properties on the islands’ indigenous mulberry trees, Morus kagamayae, or island mulberry, which make it a highly sought-after material for makers of wooden objects. One of these characteristics is ‘chatoyance’ or the ‘cats’-eye effect’ (from the French oeil de chat), usually associated with semiprecious stones like Tiger’s Eye (Pietersite). These have a particular silky sheen, like a band of light that moves as the object is turned. 

Sample of Shimakuwa mulberry wood showing complex grain and ‘chatoyance’.  Photo: Carlos Santos Barea

The best quality Shimakuwa also has a very complex three-dimensional grain pattern that takes many pages of Japanese to describe and is hard to render succinctly in English. It has been likened to a stone being placed or dropped into a sea rock pool - with the lower rippled sand being overlaid by a pattern of concentric water ripples.

Tea ceremony

One of the preferred traditional uses of Shimakuwa wood is for objects associated with the tea ceremony. The Japanese have a long and well-documented history regarding woodworking and the various skills associated with furniture making.  These include the Sashimono tradition, which uses only Japanese-sourced wood and as few nails or metal parts as possible. Just like the Shimakuwa mulberry wood, the Japanese craftsmen who use it are considered national treasures.

There are a number of small objects associated with the various ceremonial aspects of drinking tea, including tea caddies, trays and various small wooden items -- including chopsticks.  The creation of small wooden and mixed media items has remained central to the Japanese aesthetic and a number of craftsmen continue to produce objects for the tea ceremony, which are often exhibited rather than used.  The various materials used in their creation include precious metals, cinnabar, lacquer, semi-precious stones and unusual woods, like Shimakuwa mulberry.

Left: Japanese tea ceremony items and tray in mulberry wood, by various makers.  Photo: Carlos Santos Barea. Middle and Right: Kichizo Co. tea box in Shimakuwa mulberry wood for Suruga, by Yoshitaka Sugiyama.  Photo courtesy Yoshitaka Sugiyama

Netsuke

Traditional Japanese garments have no buttons or pockets, so men would carry items like pipes and money in pouches or boxes suspended on cords tied with a carved toggle, called a netsuke.  Often exquisite works of craftsmanship, netsuke developed as miniature works in their own right, independent of any functional use.  These have become highly collectable and command high prices today.

There is a remarkable set in the Boston Museum of Art made by Kwaigyokusai Masatsugi (1813 – 1893), which includes a netsuke, ojime (sliding bead cord fastener) and tobacco pouch.  This highlights the lifecycle of the silk worm, with the exquisitely carved ojime in the form of a silk moth cocoon.  The aesthetic also included the representation of mulberry leaves and moths on a silk textile.

Netsuke, ojime and tobacco pouch in mulberry wood circa 1890, by an unknown maker.  Photo Carlos Santos Barea

Janel Jacobson, a contemporary American craftsperson maker, is continuing this tradition.  Having developed her craft in ceramics, she has since evolved her work into other resistant materials, including wood.  The mostly miniature work is incredibly lifelike -- her incredible skill and expertise has been developed over many years.  She creates objects that are visually beautiful, extremely tactile and astonishingly detailed for such miniature works. 

I recently had an opportunity to gift Janel some Shimakuwa wood that a friend and maker in Japan, Yoshitaka Sugiyama, had given to me. Mr Sugiyama occasionally uses Shimakuwa and has recently used it to make a contemporary tea box for Suruga in a craft based project based on afternoon tea (see pictures above).

The small piece of Shimakuwa wood Mr Sugiyama gave me included both the heartwood and a paler, surface wood that had been near to the bark. Interestingly, the wood showed signs of being burnt (charcoal on the bark surface), which may have been linked with volcanic activity on the island. The small tree had died due to severe environmental conditions. 

Netsuke in rare Shimakuwa mulberry wood by contemporary American maker, Janel Jacobson, now in a private collection. Photo courtesy Janel Jacobson

Left: Inside of one of Janel Jacobson’s netsuke. Photo courtesy Janel Jacobson.
Right: Detail of netsuke by Janel Jacobson, showing silk moth, silk worm, cocoon and mulberry leaf. Photo courtesy Janel Jacobson.

Janel decided to make a pair of netsuke-like pieces that took their inspiration from the life cycle of the silk moth, worm, cocoon and mulberry leaves.  She did this in two ways, using precise carving techniques, working into the wood in the same way that a cameo maker would work into a shell.

These are probably among the few objects in the world in Shimakuwa mulberry wood that have been made outside of Japan. The raw wood from the mulberry trees on the Izu islands is so highly regarded by makers living in Japan that it never leaves the country.

The Izu island mulberry trees are both honoured and protected, but many are in poor condition and are dying.  As it is now almost impossible to source the wood from the Islands, it has become progressively rarer – and possibly the most expensive wood in the world. 

Article by Dr Stephen J Bowe

Stephen J Bowe’s book, Mulberry: the material culture of mulberry trees published in 2015 by Liverpool University Press, contains a wealth of information and beautiful photographs of objects made from mulberry wood. Unbeknown to Morus Londinium Stephen also carried out his own national survey of British heritage mulberry trees, listing about 100 specimens in his book. He has also produced an exquisite limited boxed edition of the book printed on mulberry paper, complete with preserved mulberry leaf and mulberry wood toggle clasp.