1 name of true and false walnut
The genus Juglans of the genus Juglans comes from Jupiter and Glans, which is originally a fruit. Among the walnut genus, the walnut (J.regia) native to Iran is famous for its fruit. According to legend, Zhang Huan introduced the country from Iran, so he has the name of walnut and peach. Walnut kernels are wrapped in hard shells, which are more suitable for walnuts. It has been introduced for more than two thousand years and is currently cultivated in northeast to southwest and south of China.
Walnut wood is pleasing and elegant, with heartwood to light reddish brown, light chestnut brown to tan with purple, and irregular black-brown stripes on the cut surface. The size of the tube hole in the annual ring is gradually changed, and the root material, the tree tumor and the tip material can form a soft or strange pattern. The wood is moderately soft and hard, the size is stable, the impact toughness is good, and the processability is excellent. It has always been the material of choice for the stock. In addition, in the high-end furniture, musical instruments and interior decoration, it is the same as teak, mahogany and ebony, which is a famous decoration in the world and plays an important role in the domestic and foreign timber market. The genus of the genus is True walnut, of which the black walnut (J. nigra), which is produced in the eastern United States and has a light black-brown and slightly purple heart, is the most famous. Walnut wood sometimes forms a tree-like pattern with great craft and decorative value on the wood due to the tree tumor. The tree tumor of the walnut tree is different. The bark surface of the tree tumor is very rough and forms many transverse groove-like spots. The diameter of the tree tumor is 5-6 cm in diameter, special round spores, and the surface of the tree tumor after peeling. Many conical wood protrusions can be seen, and the cut surface perpendicular to the wood tumor protrusion can form a circular and eye-like pattern, or a strange texture. In order to promote the formation of the tree tumor pattern, sometimes artificially stripping or tightening on the trunk, and cutting the razor in the lower part of the tree tumor.
In the international timber market, the trade name walnut is used, except that the wood of the above-mentioned walnut is true walnut, and the rest are False walnut. It includes timber of several families, and its main enumeration is as follows:
The tiger mites of the Meliaceae family, also known as Lovoa trichilioides, are often named after African walnuts. Endianodra palmerstoni, Queensland, Lauraceae, known as Queensland walnut, or Australian walnut; Phoebe porosa, Brazilian walnut; Bleilschmiedia obtusifolia, known as Blush walnut ). Beilschmiedia tawa, called Yellow Walnut. The leguminous Leguminosae's Albizzia lebbeck, called East Indian walnut; the ring-shaped elephant ear, Enterolobium cyclocarpum, called Mexican walnut. The mango face of the Anacardiaceae, Dracentomelon mangiferum, is called New-guinea walnut; the face of the Dracentomelondao, called the Philippine walnut; the black lacquered wood Metopium brown i, called Honduras walnut.
The wood of all kinds of fake walnuts has some or some similarities with the wood of the true walnut in terms of color, pattern, material and even macroscopic structure. It uses the reputation of walnut in the world timber market and reaches commercial promotion. The purpose is to use the name of the walnut walnut. In fact, they belong to different families of woods such as Polygonaceae, Polygonaceae, Leguminosae, and Rhododendron, which have the common characteristics of the corresponding families in the wood structure, and the structure of the wood of the walnut family of the walnut family. In particular, there are significant differences in the microstructure. The identification of wood structures can completely distinguish between true and false walnuts.
A brief introduction to the distribution, structural points, properties and uses of various true and false walnuts is now available.
2 Walnut Jugulans
The genus is authentic walnut, deciduous trees, thin shrubs, and branches with a transverse medulla, about 15 species. It is distributed in southeastern Europe, eastern Asia and North and South America. The black walnut (J. nigra) is the most famous, and the walnut (J.regia) is the most common. There are four species in China. In addition to walnut trees, there are also J. mandshurica from the northeast, J. cathayensis from Yunnan and Jiangsu, and J. sigillata from Tibet and Guizhou.
According to kribs, the comparative study of 9 species of walnuts is divided into two groups: 1) The heartwood of the American black walnut and walnut group is deep chestnut brown, often with purple; the sapwood is wide and the material is hard and heavy. 2) The white heart of the American white walnut (J. cinerea), Japanese walnut (J. Sieboldiana) and walnut stalks are light chestnut brown; the sapwood is narrow and the material is soft and soft.
The difference between the walnut heartwood and the sapwood is obvious. The black walnut group has a wide sapwood and the heartwood color is dark; the white walnut group is the opposite. The sapwood is light yellowish brown with ash. Heartwood reddish brown to dark brown, slightly purple, with dark or light stripes between them, chocolate color for a long time. The annual ring is obvious, the semi-dispersed hole material, the pipe hole has a decreasing trend toward the outer edge of the annual ring, and the walnut stalk has a tendency to loose the hole material. Single tube hole and diameter oblique column compound tube hole. Most species have a zigzag arrangement, with the exception of walnut mites and the like. The axial thin-walled tissue is mainly tangential to the tube. The wood ray is fine to slightly fine, the ray pattern of the diameter mask, and no wavy marks on the chord surface. Single perforation. Wood ray has the same shape of single row and multiple columns, even type III, and multi-row ray is 2-4 cells wide. The rays of wild walnuts are relatively narrow and high, and the multi-row rays are only 2-3 cells wide. The groove between the ray and the tube is the same as the hole between the tubes.
The physical and mechanical properties of several walnut woods are shown in the table.
Among the three types of walnuts in the United States, walnuts have the highest density and strength of wood, followed by walnuts and wild walnuts. In addition to the dry shrinkage value of walnut wood produced in China, the total material is similar to the black walnut produced in the United States.
3 fake walnut wood
3.1 African walnut
African walnut is actually the Lovoa trichilioides. Distributed in the coastal areas of West Africa. The sapwood is light yellow and narrow. The heartwood is dark yellowish brown. The dark stripes of gums often appear in the diameter section, which is one of the main features of the tree species. The texture is staggered, the track mask is ribbed and looks like African mahogany. The porous material, the tube holes are mostly single and double-tube aperture columns or oblique columns, the gum lanes are arranged in a chord direction, and the wheel boundary has a dark fiber layer. The axial thin wall tissue is small, and the fistula is bundled. The total dry density of wood is 0.54g/cm3, which is 15% lower than the hardness, compressive strength and flexural modulus of American walnut; the bending strength and impact toughness are 20% lower; and the anti-cracking power is 20% higher. Wood is often used instead of mahogany after dyeing. It is easy to tear the surface due to the interlaced texture processing, the cutting surface is smooth, and the performances of polishing, nailing, dyeing and gluing are good. Wood is widely used in decorative veneers, furniture, joinery, paneling and interior decoration.
3.2 Australian walnut, Brazilian walnut, etc.
Australian walnut is Endianodra Palmerstoni, also known as Queensland walnuts and oriental walnuts. Produced in northern Queensland, the tree is 42m high and can be up to 1.8m in diameter. The appearance of wood is similar to that of European walnuts, which are not obvious. The color of the material varies greatly, from light brown or reddish brown to dark brown; often with red, grayish green or black stripes. The loose-pored material, the axial thin-walled structure, the bundle tube shape and the strip shape and the wheel boundary shape, and the longitudinal section has a light-colored pattern. The rays are partially stacked. The main difference between this species and European walnuts; this species has large regular stripes; the raw material has an unpleasant smell, disappears after drying; the structure is fine, the density is slightly larger, the gloss is strong; the ray cells have silica and the like.
The wood has a full dry density of 0.68g/cm3 and the wood strength is slightly lower than that of European beech. The processing is easy to make the tool dull, the nail is difficult, the nail holding force is high, sanding and gluing are good. Wood is used for high-end furniture, flooring, interior decoration and decorative veneers.
There are several other types of walnuts in the family, such as Phoebe porosa, which is called Brazilian walnut and is produced in southern Brazil. The color of the heartwood varies from yellow to olive to dark brown. The texture is straight or curly and the structure is fine. The density of air dry material is 0.66g/cm3, easy to process, resistant to corrosion of heartwood and medium abrasion resistance. It is used for high-grade flooring, furniture, butts, interior decoration, plywood and veneer veneers.
Beilschmiedia obtusifolia is a red walnut; B. tawa is called yellow walnut. Both are produced in Australia and the latter are also distributed in New Zealand. Tawaqiongan wood grayish brown or light brown. The texture is straight or oblique, the structure is fine and slightly shiny. Loose hole material, tube hole alone or short diameter column compound tube hole, single perforation. The axial thin-walled tissue is wing-shaped, poly-winged, sometimes concentric, and has more oil cells. The wood has a dry density of 0.47-0.67g/cm3, which is slightly soft to slightly hard and slightly brittle and not resistant to corrosion. Commonly used for flooring, joinery, plywood, packaging and pulp.
3.3 East Indian Walnut, Mexican Walnut
East Indian walnut is the legume Acacia (Albizzia lebbeck). Native to tropical Asia and Africa. Asia is mainly produced in Andaman and is distributed in Ceylon, India, Myanmar, the Philippines, Indonesia and Malaya. China's Fujian, Guangdong, Guangxi, Hainan and Sichuan are distributed or cultivated. The sapwood is yellowish white, 3-5 cm wide, and the new section of the heartwood is golden brown. It is dark brown to dark brown, and the texture is wavy. Irregular textures and special colors have a high decorative value. Diffuse material, the tube hole is slightly larger and rare, single tube hole and a few short diameter column compound tube hole. The axial thin-walled tissue has a bundle and a wing shape. The ray organization is a single-column and multi-column. The wood has a dry density of 0.7-0.87g/cm3, and the material is slightly thick and medium in hardness. Easy processing, good planing performance, good wood durability, mechanical strength similar to American black walnut, regular black walnut for furniture and decorative materials, also used for vehicles and decorative thin wood.
Enterogobium cyclocarpum is called Mexican walnut. Distributed in Central America and the West Indies, northern North America. The chestnut brown wood, micro-wave-shaped tube holes, is similar to walnut wood.
3.4 Philippine walnut, New Guinea walnut
The Philippine walnut is the face of the lacquer family (Dracontomelondao). It is mainly produced in the Philippines and is widely distributed in Malaya, Indonesia and West Irian. The sapwood is gray or light brown and is more than 20cm wide. The heart is tan, with dark gray markings. The texture is straight or micro-interlaced. The porous material, the tube hole is slightly larger and rare; the long diameter column and the tube hole group are obvious, and the infill body is contained. The axial thin-walled tissue has a bundled shape and an inconspicuous wing shape. Different type II and III rays. Wood fiber is separated. The dry density of wood gas is 0.58-0.74, the structure is slightly thin, the wood track mask strip pattern, the denser the strip pattern, the darker the color, the higher the decorative value, and the decorative veneer looks like American black walnut. Often used as a substitute for black walnut, used in furniture, cabinets, sliced ​​wood and interior decoration materials.
This is another mango face (Dracontomelon mangiferum called New Guinea walnut. It is distributed in New Guinea, Indonesia and Malaya. The sapwood is wider, 25cm or more, pale yellow. Heartwood reddish brown with dark red or black markings The texture is staggered and has a wavy pattern. The structure is coarse and the wood has a dry density of 0.54—0.69g/cm3. The heartwood is similar to walnut wood and is a valuable decorative material.
The black lacquered wood of the lacquer family (Metopium brownii) is called Honduran walnut. Distributed in the West Indies of Central America. According to the wood specimens of the Nanjing Forestry University, the wood is reddish-brown, with dark stripes, scattered pores, and bundled thin-walled tissue. The wood is hard and oily. The appearance of wood differs greatly from that of walnut, and the color of the wood is similar to that of mahogany. It is also a valuable decorative material.
Lunch Box,Hot Lunch Box,Bentgo Box,Cute Bento Box
MeMe Baby Product (GZ) LLC , https://www.gzkupbo.com