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Yumu / Jumu
Northern Elm (Ulmus L.) China has more than 20 varie9es of elm tree. Tradi9onally, they have been a more affordable op9on for furniture making and recently have aOracted aOen9on in the west as offering possible alterna9ves to the western elm popula9on which has been devastated by Dutch elm disease. It is the most common furniture-making wood found throughout northern China. It is oIen referred to as Northern Elm to differen9ate it from the somewhat similar appearing Zelkova, which is also commonly called elm, or Southern Elm.
There are over twenty varie9es of elm which are widely distributed tree throughout China, but more highly concentrated in the northern regions. Northern varie9es noted for producing furniture-making 9mber include the Japanese Elm (chunyu (U. davidiana var. japonica)), which reaches 30 meters in height and 1 meter in diameter, and the somewhat smaller Manchurian Elm (lieye yu (U. laciniata)). These, along with the more broadly distributed Siberian Elm (bai yu (U. pumila)) all share similar characteris9cs.
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The sapwood of Northern Elm is yellowish-brown; the heartwood, a slight chestnut brown. The wood is difficult to dry and easily develops cracks. The material is of medium density (.59-.64 g/cm3) and hardness, and with the excep9on of Siberian elm, has rela9vely low strength. The material is somewhat resistant to decay and easy to work. Because the wood is ring porous, with a wave-like paOerning in the growth rings of the late wood, the tangen9al surface oIen reveals a layered, feather-like figure that is popular for furniture-making. (See example on facing page).
JUMU
Southern Elm (Zelkova Schneideriana) This is also a member of the ulmaceae family. It’s fast growing (and therefore highly figured and available) and much appreciated in Japan. It’s a popular furnituremaking wood in the Suzhou region. It is dis9nguished from its northern counterpart (yumu) by a more refined ring porous structure that is apparent in the tangen9al surface, and by small medullary rays that are visible as fine reflec9ve flecks across the radial surface. Southern Elm is also compara9vely denser and stronger.
Southern Elm is widely distributed throughout China with concentra9ons found in Jiangsu, Zhejiang, and Anhui provinces as well as Korea and Japan, where it is commonly known as keyaki. The tree reaches 30 meters in height and the trunk, 1.5 meter in diameter.
The sapwood is dis9nguished from the slightly darker heartwood, which varies in tonality from yellowish brown to coffee-brown. Jiangsu craIsmen tradi9onally divide jumu into three types: yellow ju (huangju), red ju (hongju), and blood ju (xueju). Factors including the age of the tree are thought to account for these varia9ons in color as well as ranging densi9es (63 - 79 g/cm3). Blood ju, with a reddish-brown coffee color as well as some feathery like figure in the tangen9al surface, is the most highly prized.
A provincial 18thC stool with 3-way lap joint on stretchers from the northern province of Shanxi.Yumu Elm
(Author’s Collection)
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