Kaya
Torreya nucifera, one of the types of wood from which traditional gobans are made in Japan.
The kaya is an evergreen tree with yellow to pale brown wood and spreading brownish branches. The kaya is durable under water. In autumn the plant is laden with large seeds (like acorns or hazelnuts) which contain oil and have a resinous aftertaste. The color of cut kaya wood mellows with age.
Most often the kaya is found as underwood in mountain forests, seldom in open areas. Kaya is a slow-growing tree requiring several hundred years to mature. This is one of the reasons it has such a close beautiful grain, and also why it is expensive.
Kaya gobans are classified into two types: itame for irregular or bent grain, and masame for straight grain. Prices for a kaya goban with attached legs (15-20 cm height) range from about $6,500 US (itame) up to $25,000 US (masame). A kaya table goban (5 cm height) costs about $1,000 US.
Some vendors call the wood in some of their boards Shin Kaya. This is not kaya, but a completely different wood.
Cancer drug, protected species?
Some writers call kaya taxus nucifera rather than torreya nucifera. This is how it was first classified by Linnaeus in 1753. Later, a Scottish Botanist, George Arnott, decided that Linnaeus’ Taxus nucifera belonged in a different genus, Torreya.
If kaya actually belonged in Taxus, we would have to stop using it.
Asian yews, genus taxus, produce the anti-cancer drug taxol/paclitaxel, but there are not nearly enough trees to provide all that could be used. They are on the World Wildlife Federation's
10 most wanted list of endangered species. After some fairly horrendous over-exploitation, they are now legally protected in China.
One paper on illegal logging Word format
says:
- A chemical compound extracted from the bark, needles, twigs and roots of species of the genus Taxus called paclitaxel has been sucessfully used to treat some cancers – the drug is now the biggest selling cancer drug in the world. ...
- All species of Asian taxus are suffering from massive over-exploitation ... Just one treatment of paclitaxel requires the bark of 7.5 average sized trees. 3000 trees are needed to produce just 1kg of the drug, and current world demand is for more than 700kg.
One estimate is that by harvesting the entire world population of Taxus trees, you would get enough to give every patient that could use it one dose of the drug. Of course, effective treatment requires many doses.
The genus Torreya has been regarded as a member of the yew family, Taxaceae, along with the genus Taxus. However, some botanists put it in other families.
There are only six torreya species known: kaya in Japan and Korea, 3 in China, and two in the US, the fairly rare California torreya and the endangered
Florida torreya.
Related (botanical) links:
- "Torreya nucifera" at
Plants for a Future Gives taxus nucifera as a synonym.
- search for "Torreya nucifera" at
Spring Flowering