Oak (Zuomu, Gaolimu) furniture
Although furniture made from oak is somewhat rare, the material has long been known as an excellent furniture-making wood. The variety known as gaoli was used in the Yongzheng (1723-1735) Imperial workshops, and earlier examples have also survived. Botanists have identified one hundred forty types of oaks widely distributed throughout China. These are divided into the evergreen Qingfeng group and the Mali group, the latter inclusive of both deciduous and evergreen varieties. Three species suited for furniture-making are noted below.
The Blue Japanese Oak (C. glauca) is widely distributed from Japan to India and commonly reaches heights of 20 meters with trunk diameters of one meter. The sapwood and heartwood are not clearly distinguished and range from grayish-yellow to grayish-brown with streaks of brown or red. The material is difficult to dry and not easy to work, however, it is extremely dense (±.90 g/cm3) and hard. Distinctive medullary rays appear in the tangential surface as short dark lines; in the radial surface, they appear as lustrous flecks woven through the longitudinal grain. The Sawtooth Oak (Q. acutissima) is also broadly distributed throughout China. With the exception of its reddish-brown heartwood, other characteristics are similar to the Blue Japanese Oak.
The somewhat less dense (.67-.75 g/cm3) Mongolian Oak (Q. mongolica) grows throughout north central and northeastern China, and is found from stretching westward through Japan , Korea, Mongolia, and Siberia. A similar species of growing in the Xing'anling region of Mongolia has been related to that commonly termed gaoli mu---Gaoli being a Chinese reference to ancient Korea.