Boxwood: A Preliminary Study of a Famous Carving Wood and Its Substitutes
1 Basic Information on Boxwood (Buxus spp.) Boxwood belongs to the family Buxaceae and the genus Buxus, with the English name boxwood. It is an evergreen shrub or small tree, with about 70 or more species worldwide, distributed in Europe, Asia, tropical Africa, and Central America. China has about 17 species, and Yunnan about 8 species. According to the record in "Chinese Woods": "In the Shennongjia forest region of Hubei, the Wuyi Mountains of Jiangxi, and Sichuan Province, there are small-tree timber forests distributed or cultivated in continuous stands, and the Laoshan Forest Farm in Shandong has boxwood with a diameter at breast height of about 30 cm." In addition, according to relevant literature, although Yunnan has 8 species and they are distributed throughout the province, they mostly grow scattered in broad-leaved forests, shrub thickets, or on valley limestone, and no continuous natural pure stands or large-area plantations have been seen. Because it grows very slowly, naturally grown boxwood needs about 400 years to reach a diameter at breast height of 20 cm, which is one of the reasons it is a precious and famous wood. From the mid-1980s to the early 1990s, during the nationwide frenzy of deforestation of forest resources, small batches of commercial timber were occasionally seen in Yunnan being transported and sold outside the province; the diameter classes were mostly 10-20 cm and the logs were 1-1.5 m long, causing the precious forest germplasm resources left by our ancestors to suffer serious damage. Only after the state explicitly banned the logging of natural forests in 1996 was the situation reversed, and now it is likely that no commercial timber is supplied anywhere in the country. Not long ago, a manufacturer in Shanghai telephoned Kunming to ask about the resource situation of boxwood and also asked whether the United States exports commercial timber. After consulting relevant foreign literature, although it is distributed in Europe, tropical Africa, and Central America, there is also no supply of commercial timber in batches. Therefore, in order to meet production needs, the work of selecting suitable substitute woods is imperative.
2 Identification and Use of Boxwood (B. microphylla S. et Z.) Boxwood is an evergreen small tree or shrub, with grayish-yellow-brown bark about 5 mm thick, finely longitudinally fissured. It is distributed in the Yangtze River basin and the provinces and regions to its south. In Yunnan it is mainly distributed in broad-leaved forests, shrub thickets, or valley limestone shrub forests in central Yunnan and the mid-altitude areas to the north. The wood is diffuse-porous. The wood color is bright yellow or light yellow-brown; the distinction between heartwood and sapwood is not obvious; it is lustrous; the surface of green wood has a slight earthy smell; the taste is slightly bitter; growth rings are indistinct to slightly distinct, of uneven width (0.20-0.30 mm, average 0.25 mm). The latewood band is slightly darker in color. Pores are very numerous, minute to very small, completely invisible to the naked eye and only vaguely discernible under a magnifying glass; usually solitary, rarely in short radial multiples (2); within a growth ring they gradually decrease and become smaller from inside to outside, and their distribution is uneven; they are scattered. On longitudinal sections, fine light yellow-brown lines formed by the latewood band are faintly visible. Axial parenchyma is not visible. Wood rays are medium to slightly dense; very fine to slightly fine, faintly visible to the naked eye and clear under a magnifying glass. Ripple marks and intercellular canals are absent. The wood grain is oblique; the texture is very fine to extremely fine and uniform; the material is slightly hard and heavy (air-dry density 0.85 g/cm³); drying is slow, and after drying the dimensional stability is stable, without warping or cracking; resistance to insects and decay is strong; sawing is easy, and turning and carving performance is especially good, with an extremely smooth and fine cut surface; after painting it is bright and beautiful; gluing is easy, and nail-holding power is relatively strong. The woods of species in the genus Buxus are very similar among species, with very slight differences. The texture is fine and uniform, the wood color is elegant and pleasing, and there is no hard feeling when cutting, making it most suitable for small carvings and turned art crafts of various kinds. For a long time, it has been used as wooden bases for ivory and jade carvings, as well as a high-quality raw material for precious seals. It is also commonly used for turning cosmetic @#@217@#@ and toys, wooden combs, inlaid crafts, folk musical instruments such as the handle and tuning pegs of the erhu, exquisite wooden boxes, wooden rulers, shuttles, abacus beads, tool handles, chess pieces, tobacco pipes, walking sticks, and so on.
3 Brief Introduction to Alternative Substitute Wood Species
3.1 Adina (Adina cordifolia; A. spp), also called "shui huang mian," commonly known as boxwood, English name adina. A deciduous tree of the family Rubiaceae, up to 30 m tall and 1 m in diameter at breast height. It is produced in the hot regions of western Yunnan and is also distributed in Hainan Province, India, Sri Lanka, Vietnam, Laos, Cambodia, Myanmar, and Thailand; imported timber is often available at the Yunnan-Myanmar border ports. The wood is diffuse-porous, bright yellow to dark yellow-brown in color; there is no distinction between heartwood and sapwood; it is lustrous; green wood has a pungent odor that disappears after drying; the taste is slightly bitter. Growth rings are indistinct to slightly distinct, of uneven width, separated by dark-colored bands, 1-4 rings per cm. Pores are slightly numerous to numerous; solitary and in short radial multiples (2-4); very small to slightly small, slightly visible under a magnifying glass; slightly uniform in size, fairly evenly distributed; tyloses not observed; scattered; axial parenchyma not visible. Wood rays are very numerous, very fine to very fine, slightly visible under a magnifying glass; ray flecks on radial sections are not obvious (invisible to the naked eye). Ripple marks and intercellular canals are absent. The wood grain is straight or oblique; the texture is very fine and uniform; hardness and weight are medium (air-dry density 0.69 g/cm³); drying is slow, without warping or cracking, and dimensional stability after drying is stable; resistance to insects and decay is strong; cutting is easy, the cut surface is smooth, and turning performance is good. It is generally used for toys, wooden rulers, pen holders, yarn bobbins, thread cores, shuttles, and can also be used for decorative carving, picture frames, photo stands, piano keys, etc.; because of its beautiful color, it is also commonly used for furniture, instrument cases, wooden combs, industrial and agricultural tool handles, brush backs, and other daily utensils. Because of its strong resistance to insects and decay, people in the producing areas often use it for building roof frames, purlins, doors and windows, etc. In India it is a common industrial timber. In summary, based on its wood color, wood quality, and processing performance, it can be considered a relatively ideal material to replace boxwood. This genus has about 30 species, distributed in tropical and subtropical regions of Asia and the Americas; China has about 10 species, and Yunnan has 4 species. About 8-9 species in Southeast Asia can supply commercial timber. The wood color and wood quality are similar, with air-dry density between 0.66-0.98 g/cm³, and the uses are also roughly the same. The woods of the following genera in the Rubiaceae can also be considered: 1) Canthium (Canthium spp), English name butulangcanthium. This genus has about 200 species. It is produced in tropical Asia, Africa, and Oceania; China has 5 species, and Yunnan has 4 species. Among them, Canthium dicoccum is an evergreen tree, produced in Guangdong and Guangxi, Hainan, and Yunnan. It also occurs in Indochina, the Malay Peninsula, Indonesia, the Philippines, and Australia. Its wood is also diffuse-porous, brown or yellow-brown; lustrous; texture very fine and uniform; material slightly hard and heavy (air-dry density 0.81 g/cm3); large-leaved canthium (C. simile, 0.59 g/cm3), produced in Guangxi, Hainan, and Yunnan; the two are slightly similar to Adina in wood color, wood quality, processing performance, and uses. 2) Nauclea (Nauclea spp) and Neonauclea (Neonauclea spp); English name ffsthead-tree. The former has about 30 species, distributed in tropical Asia, Africa, and Oceania; China has 1 species, produced in Guangdong and Guangxi and Yunnan; Southeast Asia has more than 10 kinds of exported commercial timber; the latter has about 50 species, distributed in tropical Asia, with about 15 kinds of exported commercial timber in Southeast Asia; China has 4 species, and Yunnan has 3 species. The woods of both genera are yellow to orange-yellow diffuse-porous woods, with fine, uniform texture; material slightly hard and heavy (air-dry density 0.55-0.88 g/cm3); processing performance is similar, utilization is roughly the same, and all can be tried as substitutes. 3) Gardenia (Gardenia spp), English name gardenia or box-wood. About 50 species, distributed in tropical and subtropical regions worldwide; China has 6-7 species, distributed in Guangdong and Guangxi, Yunnan, Hainan, and Taiwan, China. Yunnan has 4 species, but only large-flowered gardenia (G. seotepensis) is a deciduous tree. Southeast Asia has 5-6 kinds of exported commercial timber. The wood is milky white or light yellowish-white diffuse-porous wood; grain straight; texture very fine and uniform; material slightly hard and heavy (air-dry density 0.77-0.86 g/cm³). The uses are roughly the same, and it can be tried as a substitute. 4) Randia (Randia spp), English name randia. About 230 species, distributed in tropical regions worldwide. China has 18 species, produced from the southwest to the southeast; Yunnan has 12 species, among which Vietnamese randia (R. cochinchinensis), randia (R. canthioides), and Lingluomai (R. wallichii) are the 3 most common evergreen trees. Southeast Asia has 3-5 species of commercial timber for export. The woods are all diffuse-porous; yellow to yellow-brown; grain oblique; texture very fine and uniform; material slightly hard and heavy (air-dry density 0.72-0.82 g/cm³). For the Rubiaceae species listed above, the wood color and wood quality are all very similar, and the uses are also roughly the same, so all can be tried as substitutes.
3.2 Symplocos (Symplocos spp), also called "shan fan," English name sweet-leaf, a plant of the family Symplocaceae, about 300 species, distributed in tropical Asia, the Americas, and Africa; China has about 80 species, mainly distributed in forest regions across the south. Southeast Asia supplies a small amount of commercial timber. The wood is diffuse-porous, yellow-white to yellow-brown with a slight red tinge; the distinction between heartwood and sapwood is not obvious; grain straight; texture fine to very fine and uniform; weight medium to heavy (air-dry density 0.55-0.85 g/cm³; Nanling symplocos S. confusa 0.80 g/cm³); drying speed medium; processing performance good, cut surface smooth and clean, suitable for turning. It is generally used for industrial and agricultural tool handles, wooden rulers, brush handles, chess pieces, toys, carving, inlay, house construction, and interior decoration. There are many species, and those with relatively high density can be selected as substitutes. For example, Yunnan-produced black-barked symplocos (S. discolor, wood light yellow-brown, air-dry density 0.71 g/cm³) can be tried as a substitute.
3.3 Euonymus (Evonymus spp), English name spindle-tree. A plant of the family Celastraceae, about 150 species, distributed in the North Temperate Zone. China has about 90 species, found throughout the country; Yunnan has 70 species, mostly shrubs or small trees. Several Yunnan-produced species such as long-leaved euonymus (E. oblongifolius), southwestern euonymus (E. hamiltonismus), and large-flowered euonymus (E. grandiflous) are trees. The wood is diffuse-porous. The wood color is yellow-white, with no distinction between heartwood and sapwood; lustrous; grain straight or oblique; texture very fine and uniform; weight and hardness medium (Yunnan-produced large-flowered euonymus air-dry density 0.73 g/cm³; Guangdong many-flowered euonymus E. nyriantha 0.78 g/cm³); processing performance good; cutting easy, especially good for turning. It is most suitable for carving, turning, stationery (wooden rulers, set squares, pencil holders, pen holders, drawing boards, etc.), seals, wood engraving, wooden bases for jade and ivory carvings, turned toys and ornaments, inlay crafts, wooden combs, thread spools, chess pieces, clogs, etc., and is a relatively ideal raw material to replace boxwood.
3.4 Wrightia (Wrightia spp), English name common wrightia. A plant of the family Apocynaceae, about 30 species, distributed in tropical regions worldwide. China has 6 species, Yunnan has 5 species, and Southeast Asia has more than 10 species that can supply commercial timber. The wood is diffuse-porous. The wood color is light yellow-brown; the distinction between heartwood and sapwood is not obvious; lustrous; no special odor or taste; grain straight; texture very fine and uniform; hardness and weight medium (air-dry density 0.51-0.62 b/cm³); easy to process; drying fast, turning performance good, cut surface smooth and clean; it is an excellent material for carving and turning. It is suitable for carving seals, decorative wood carvings and other arts and crafts, toys, chess pieces, pen holders, picture frames, inlay, and pencil holders, etc. It is very beautiful when used for furniture and interior decoration, and is a high-quality raw material to replace boxwood.
3.5 Camellia (Camellia spp), English name camellia. A plant of the family Theaceae, about 200 species, distributed in eastern and southeastern Asia; China has about 190 species, distributed in the provinces and regions south of the Yangtze River. Yunnan has 60 species, mostly evergreen shrubs or small trees to trees. The wood is diffuse-porous to semi-ring-porous, yellow-brown to light red-brown in color; the distinction between heartwood and sapwood is not obvious; lustrous; no special odor or taste; growth rings generally slightly distinct, of uneven width; pores numerous; very small, slightly visible under a magnifying glass, somewhat evenly distributed; scattered. Axial parenchyma not visible. Wood rays sparse to slightly dense, very fine to medium. The wood grain is oblique and interlocked; texture very fine and uniform; weight and hardness heavy to hard-heavy (air-dry density 0.73-0.95 g/cm³); Guangdong-produced Guangning oil tea C. semiserrata 0.85 g/cm³; Guangxi-produced pointed-leaved tea C. cuspidata 0.75 g/cm³); drying slow; decay-resistant; cutting medium to slightly difficult, cut surface very smooth and clean, especially suitable for turning. It is usually used for industrial and agricultural tool handles, farm tools and household items, walking sticks, toys, wooden combs, carving (such as printing blocks, seals, and ornaments, etc.), and can be tried as a substitute.
3.6 Loquat (Eriobotrya spp), English name loquat. A plant of the family Rosaceae, evergreen trees or shrubs. About 30 species, mainly distributed in the temperate and subtropical regions of Asia; China has 13 species, and Yunnan has 9 species. The wood is diffuse-porous. The wood color is light red-brown to grayish red-brown with a slight yellow tinge; the distinction between heartwood and sapwood is not obvious; lustrous; no special odor or taste; growth rings slightly distinct, of uneven width, the latewood band slightly darker. Pores very numerous, very small. Only slightly visible under a magnifying glass, slightly uniform in size, fairly evenly distributed; scattered. Axial parenchyma not visible. Wood rays medium to slightly dense, very fine to slightly fine, visible under a magnifying glass; ray flecks visible to the naked eye on radial sections; wood grain oblique and interlocked; texture very fine; uniform; material slightly hard and heavy (air-dry density 0.73-0.97 g/cm³; Guangdong-produced loquat E. cavaleriei 0.81 g/cm3, mountain loquat E. fragrans 0.97 g/cm3; Guangxi-produced loquat E. japonica 0.88 g/cm3, mountain loquat 0.93 g/cm3); processing slightly difficult, but turning performance good. It is generally used for turning, carving (seals, decorative arts and crafts, etc.), wooden combs, industrial and agricultural tool handles, steelyard rods, etc., and can be tried as a substitute.
3.7 Photinia (Photinia spp), also called "shi ban mu," English name photinia. Also a plant of the family Rosaceae, deciduous or evergreen, trees or shrubs. About 60 or more species, produced in southeastern Asia and North America. China has about 40 species, and Yunnan about 20 species. The wood is diffuse-porous. The wood color is yellow-white to light red-brown; the distinction between heartwood and sapwood is slightly obvious; growth rings slightly distinct, with light-colored bands between rings; lustrous; no special odor or taste. Pores very numerous, very small, also indistinct under a magnifying glass, uniform in size, somewhat evenly distributed; scattered. Axial parenchyma not visible. Wood rays slightly dense to dense, very fine to slightly fine, visible under a magnifying glass; ray flecks visible to the naked eye on radial sections. The wood grain is straight or oblique; texture very fine and uniform; weight and hardness medium to slightly heavy (Guangxi-produced elliptic-leaved photinia Ph. beauverdiana air-dry density 0.68 g/cm3; Guangdong photinia Ph. serrulata 0.88 g/cm3; Anhui-produced photinia 0.98 g/cm3; Guangxi-produced smooth-leaved photinia Ph. glabra 1.01 g/cm3, peach-leaved photinia Ph. prunifolia 0.99 g/cm3). Processing performance good, cutting easy, cut surface smooth, good for turning; drying slow; decay-resistant. It is usually used for decorative wood carving and seals, wooden combs, shuttles, instrument handles, turned toys, chess pieces, wooden buttons, abacus bead frames, steelyard rods, chopsticks, industrial and agricultural tool handles, cart wheels, etc. It can be tried as a substitute.
3.8 Mountain ash (Sorbus spp), English name mountain-ash. A deciduous tree or shrub of the family Rosaceae, about 80 species, produced in the North Temperate Zone. China has about 50 species, Yunnan about 40 species, and about 10 or more species have timber value. The wood is mostly diffuse-porous (a few ring-porous), light yellow-gray-brown to light yellow-brown in color, with the distinction between heartwood and sapwood not obvious, and the heartwood of old trees slightly darker; lustrous; no special odor or taste. Growth rings indistinct to slightly distinct, separated by dark-colored bands. Pores very numerous, very small to extremely small, slightly visible under a magnifying glass, slightly uniform in size, fairly evenly distributed, in oblique or radial arrangement. Axial parenchyma invisible to slightly visible under a magnifying glass, marginal and paratracheal. Wood rays medium to dense, very fine to slightly fine, slightly visible under a magnifying glass; extremely fine ray flecks visible to the naked eye on radial sections. Ripple marks absent; intercellular canals not observed. The wood grain is straight; texture very fine and uniform; hardness and weight medium (Northeast-produced mountain ash S. pohuashanensis air-dry density 0.61 g/cm3; Yunnan mountain ash S. wallichii 0.70 g/cm3); drying relatively slow, with dimensional stability after drying; decay-resistant; cutting easy, cut surface smooth and fine. It is most suitable for carving and turned products; the famous Jianchuan wood carvings in China are mostly made from Yunnan mountain ash, and it is commonly used among the people for carved furniture and crafts. It can also be used for seals, printing wood blocks and ornaments, abacus beads, tobacco pipes, toys, stationery, wooden combs, picture frames, walking sticks, industrial and agricultural tool handles, etc. It can certainly be tried as a substitute.