Black walnut is mainly produced in North China, Northwest China and Central China. Asia is the birthplace of walnuts, and some scholars believe that walnuts originated in China. It is reported that the Greeks brought walnuts to Italy and transplanted them to all parts of Europe, and the Romans introduced walnuts to Italy in 1 century.

Suitable environment for the growth of black walnut. Most of them grow in North America and Northern Europe. The climate in this area mainly belongs to temperate zone and sub-frigid zone, especially the continental climate in sub-frigid zone is dominant. The general feature of continental climate here is cold winter, with the lowest average temperature of 1 month. Summer is warm and hot, and July is the hottest month. The temperature is high all year round. The annual precipitation is moderate, which is suitable for wood growth. It is also because of this climate that the density of black walnut is high.

Extended data:

Black walnut is easy to be processed by hand tools and machinery, nails, screws and glue have good fixing performance, and have excellent painting and dyeing properties, and excellent surfaces can be obtained after polishing. It dries very slowly and needs careful care to avoid drying and aging. Black walnut has good dimensional stability, and is evaluated as heartwood with strong corrosion resistance, which is the most durable wood even in corrosive environment.

Black walnut is very expensive, table furniture is generally made of wood skin, and solid wood is rarely used. Planted veneer is often used in wooden parts of building engineering and high-grade classroom furniture. Because it is a dark tree species with good elasticity, it is also very suitable for making tables and chairs. Traditional wood veneer can be used for piano surface and interior decoration of middle and high-grade cars.

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